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Chevy Tahoe



  • Arrie --

    I read your response on the 5.3 V8 performance with interest especially when you mentioned that Upper Manifold tightening.

    I recently replaced both my upper and lower manifold gaskets on my 1997 5.7 V8 Tahoe -- I cannot get the engine to run smoothly -- i continue to get a DTC P0300 code. Along with replacing the Upper & Lower Manifold gaskets I also replaced the Valve Cover gaskets. Since I have 144K miles on the vehicle, I thought I should also change plugs & wires. Starting up everything I got a DTC P0145 code so I replaced the HO2 Monitor (Bank 1 Sensor 2) and that cleared that code. But I cannot clear the P0300. I've since replaced the Distributor cap & rotor, replaced the 7mm Plug wires with 8mm plug wires, installed a new ignition coil and I still cannot get rid of the P0300.

    Could it be that I just need to tighten the Upper Manifold more than the specs call for -- I diligently tightened both lower and upper manifold bolts in stages as my Chilton book specified ...

    Any thoughts or suggestions would be appreciated since I'm running out of things to change out...

  • pbaker1pbaker1 Posts: 1
    Hopefully this description will help you understand what the car is doing. I live in an area of TX that is almost flat as a pancake except for a few rolling hills.

    When the cruise control is on 70 to 73 mph and the car begins to go over a “hill”, the transmission will drop down to 2nd gear instead of 3rd gear which would be sufficient to keep the car at the same speed while going up a slight, short grade.

    The cruise works fine on flat roads and only does the dropping down to 2nd gear about 50% - 75% of the time.

    On our most recent trip last weekend, there is a slight short hill and the transmission dropped down to 2nd gear here, without going to 3rd gear, with same sudden increase in speed as if you have stomped on the gas pedal down to the floor.

    If the cruise control were off, you would only need to exert slight pressure to the gas pedal to keep the same speed on this hill, not stomp the pedal as if you needed to pass someone quickly.

    That’s what the cruise control does, it’s as if you have applied pressure to gas pedal in a sudden manner all the way to the floor.

    There are no rises that we have come across that would require the pedal to apply full gas in order to get up and still maintain the same speed.

    There have been instances where the speed has increased quite a bit when the transmission drops to 2nd and the car goes like a bat out of haites…and it doesn’t need to….so this is a safety issue as well.

    We have had the car into the dealer twice in tha past 10 days and they say it has "normal cruise control operation". I have been told to read my manual...and that the cruise control will do what ever it takes to get my car over the hill and maintain the speed I have it set for. I am taking off work next week to ride with them until the car does it again. Anyone else experiencing this problem? I have never had a car with cruise control that acted this way. We also own a 2003 Z71 Pickup and the cruise control on this car works fine.
  • jlflemmonsjlflemmons Posts: 2,242
    Sorry about the testiness of my reply. I daily hear comments along the lines of "the big three are in league with the oil companies to keep the fuel economy down in SUV's and trucks." These same geniuses don't stop to think what a huge money maker a high gas mileage, high tow capacity vehicle would be. The basic problem is physics. It takes X amount of energy to move X amount of mass. At issue is finding a power source of required energy which can be economically produced and supported. The limiting issues are battery capacity. A lightweight auto can be made to use electric hybrid technology and achieve significant gains in fuel economy. But look what was required to move the large loads of a freight train. Diesel electric engines of massive weight and producing a whole lot of solid particulate. Great plan for moving trains, not so good for trailers.

    On the other hand, several years ago a team of MIT students took a 16HP engine and connected it to a hydraulic pump. Pump drove a hydraulic motor with the excess going to an accumulator. They were getting over 50MPG in a Chevette, I believe, with a cruising speed of around 55 and burst speed to near 70. All the while the small engine ran at a constant speed. Always thought that was a very clever idea.

  • arriearrie Posts: 312

    I'm not sure about the other code you mention but isn't that P0300 code the one that GM techlink mentions to be the one with intake manifold seal leak?

    If that is the case then you could still have a leak problem with intake manifold gasket.

    The problem with gasket is not just the gasket. It also has a lot to do with the manifold port surfaces too. In that GM techlink page they also explain how to measure straightness of the manifold surfaces that press against the gasket.

    You could also have a problem with the MAP sensor. To rule this out you would need to buy a new sensor to see if it helps unless you want to take it to the dealer and have them check it out. I think buying a new sensor is lower cost than the dealer route since if they find it faulty you'll end up paying for the check-out and for the new sensor for it. MAP sensor is easy to change (at least in my Tahoe) as it is located on top of the engine under the plastic cover and the little plastic bracket for the cover.

    It's also worth to check wire harness connection to the MAP sensor. I had that problem too.

  • dardson1dardson1 Posts: 696
    I don't tow (or not often although it's nice to know I can). I don't live in a snowy area or drive off-road, so I don't buy the 4WD and could likely live with the 4.8 V8. What I need and what I use this vehicle for is the ability to fold the rear seats easily (useless third row is in the store room) to make a huge and flat floor that is great for work and handy for personal hauling (getting a washing machine home from Home Depot). The rear wheel well is a bit larger than 48" (rare). The tall cargo area allows me to get almost anything in there. Driving conservatively with my with my 5.3 V8 and standard axle, I mostly get 15+mpg around town and near 20 HWY. I've had a slew of cars. The 15+/19+ I get is about as good as I've gotten in any large vehicle. My wife's Lexus '04 RX330 which is 25% smaller and lighter averages high 17's city and 21-22 on the road. Pound for pound, my Tahoe is a bit more efficient than her Lexus, and about as cheap to drive considering the Lexus need for premium fuel.
    There is a seat-of-the-pants understanding the general public has for cars. Tahoe/Yukon is the best selling SUV for a reason. GM, using old-world technology, still does the best job making large vehicles with better-than-expected efficiency. love my Tahoe.
  • arriearrie Posts: 312
    It might not be a cruise control problem at all. If you would try to run your Tahoe at constant speed on the same route by manual control you might end up seeing the same thing, i.e. you end up pressing the gas pedal so deep that the gear shifts down two steps to make it up the hill.

    I have written a lot of info about my struggle with my '04 Tahoe with the Z-engine and after all the work I think I finally found the problem that probably was the main reason for all of my trouble. I changed spark plugs, plug wires 4 times, Oxygen sensor 4 times, MAP sensor and crank shaft position sensor. I did get a lot of help from changing the crank shaft position sensor and a little bit from one oxygen sensor and the new set of high performance spark plug wires for fuel economy.

    One symptom I had with the truck was something that sounds much the same as you describe. The truck had to change down to 2nd gear to go up a hill that you would not think is steep enough for that. My Tahoe sometimes went over an overpass without any trouble without changing down at all but half the time over the same overpass with same speed it had to change down to 2nd gear. This did not make any sense to me but my dealer told me they can not find a problem.

    Well, long story short: The biggest help for my Tahoe was to change the intake manifold gasket. I came across a GM techlink pages where they explain about the issue with orange color gaskets and say they need to be replaced with green color ones. I changed mine even though they were green color but clearly showed had not been tightened correctly. After gasket change everything changed to better, especially any need for gear changes at overpasses. No gear changes needed at normal overpasses any more and the whole truck responses to gas pedal like never before. It is just so much better than it was. You could not believe the difference.

    GM might have a problem at their engine assembly plant where they do not tighten the intake manifold correctly leaveng it loose. This then developes a vacuum leak, which messes up with the engine ignition timing. Timing being off causes lack of power and all sort of other problems, like low gas mileage.

    Have your intake manifold bolts torqued. If you have the same design engine as mine there are 10 bolts. The best thing would be first to see if your gasket works with correct tightening on bolts. It might work just fine.

    What I would do is:

    - first loosen all 10 bolts.

    -tighten all bolts to 4 ftlb torque by instructions in Haynes manual. I bought Haynes manual for Chevrolet trucks up to year 2002. The engine is little different but for this part it seems to be the same. Tightgening of the bolts I think is important to do in the right sequence, like the manual says.

    -after tightening the bolts to 4 ftlb tighten them to the final torque at 7.5 ftlb in the same order.

    As I mentioned after doing this to my Tahoe it changed so much better it is hard to believe. I also used new gaskets, which cost $90 from the dealer.

  • txyank1txyank1 Posts: 1,010
    I agree. I get only slightly less city mpg on my heavier Avalanche and about the same highway. :D
  • alston28alston28 Posts: 97
    Nothing to apologize for. I think you're right and I appreciate your feedback. I don't need a Tahoe (or any SUV), and I don't like the idea that I will be burning a lot of gas for capability I don't need. But I have these long legs that have to go somewhere. The Tahoe with the bench seat is one of the few cars I'm comfortable in.

    After thinking about this last night, I’m starting to believe that it doesn’t make economic sense to wait for the hybrid Tahoe due out in the spring 2006 (if I decide to buy a Tahoe at all). This conclusion is based on some assumptions. The assumptions are:
    1. The list price of the Tahoe I want is $39,000
    2. I could buy it for $32,000.
    3. Next year the list on this Tahoe as a hybrid will be $49,000. I could buy it at $3,000 over list, $52,000.
    4. With non-hybrid Tahoe I buy today, I will average 18 mpg.
    5. I’ll drive 15,000 miles a year.
    6. The gas mileage on the hybrid Tahoe will be 30% better, or 24 mpg. (This is based on the projection from GM.)
    7. Gas costs $5.00 per gallon.
    With these assumptions (and not including the time value of money), it would take me over 19 years of $5 gas to recoup the extra (assumed) cost of the hybrid Tahoe.
    Any comments or thoughts will be appreciated. Thanks.
  • jlflemmonsjlflemmons Posts: 2,242
    Well done. I appreciate a person who understands math! So many folks don't think this through to see the true cost expended. My wife drives a Yukon daily, and some folks question her using such a high consumption vehicle. What they don't take into consideration is that 1) We also use it to pull a 7K lb travel trailer, 2) She is a girlscout leader and can carry herself and 7 others in seat belts, and 3) She averages less than 10K miles a year.

  • davids1davids1 Posts: 411
    If new is not a requirement for you and leg room is, consider looking a used model. My 99 Tahoe (old body style) has significantly more leg room than the new body style. Find a lot that has both a 95-99 Tahoe/Yukon and a Tahoe/Yukon with the new body style so that you can sit in both minutes apart. You'll notice the difference. At 6'-5", it makes a big difference to me. One other major benefit of my 99 Tahoe is "it's paid for" and has been for some time now. YeeHaw!!! After living several years without car payments, I'll do whatever it takes to minimize financed vehicle purchases.
  • alston28alston28 Posts: 97
    Thanks. New is not a requirement for me. I'll try to old style Tahoe.
    I'm very comfortable in the new Tahoe. Until recently, I thought I wouldn't buy anything new, because I didn't want to take the first-year depreciation hit. My recent thinking has been that with the recent "employee pricing" the cost of new has been driven down, and the economics haven't caught up in the used market to drive down the cost of used. I had been think of something 1 or 2 years old. It seems that the cost of a 2004 or 2003 Tahoe is not sufficiently lower than today's cost of a 2005 to justify buying used. (I also have a brother-in-law in the business who may be willing to sell at his true cost.) Any further thoughts will be appreciated. Thanks.
  • sebring95sebring95 Posts: 3,238
    If leg/head room is the issue, my VW Jetta TDI trumps the Tahoe in comfort. The leg/head room feels equally roomy (i'm 6'4) and the seats are far better than the GM bench. While the GM bench isn't terrible, it's more like a Kmart sofa than a good seat (IMHO, seat comfort is quite subjective obviously). I guess it really depends on whether you want a big vehicle that's comfy, or just something that's comfy. You could also try an Audi if you want folks to look at you or something. I find the german cars to fit me better than anything. Oh yeah the VW gets 45-47mpg with performance mods and my typical 80mph+ speeds. A bit better than even a hybrid Tahoe can dream of.

    I really liked my Tahoe, but I do tow, haul six or more regularly, and do get into some un-plowed roads. I recently sacrificed (not really I have several other 4x4 trucks) the snow/towing capability and traded the Tahoe on a Honda Ody. Seat seems plenty comfy to me and it's a better people hauler. Gets better mpg too.
  • alston28alston28 Posts: 97
    Thanks for your imput, but you must be configured differently that I am. I'm 6/5" and all my height is in my legs. The issues for me are bucket seats and center consoles. I can hardly get in a Jetta. In an Audi A6, my knees are jammed against the steering wheel. In both, my leg rubs against the center console. I will definitely settle for something that's comfy. I don't need something that's big and comfy, but there's nothing on the market that's comfy for my build except things that are big - so far the cars I've found are the Tahoe with a bench seat and a Lincoln Town Car.
  • sebring95sebring95 Posts: 3,238
    Yeah, I'm more top than bottom. I have a lot of trouble with head-room which is part of why I found the Jettas/Audis to be comfy. Plus the seats go back quite far.

    Take a look at the minivans at least. We're getting between 19-24mpg in general driving with the Ody and performance is equal/better than the Tahoe. Drives better than a Town Car (IMHO, I hate mushy suspensions). Ody has a lot of features the Tahoe is lacking as well, which surprised me considering the price. We got a large touch-screen navigatino, backup camera, rear DVD, leather, six-disc changer, etc. all for less than I paid for my Tahoe back in 2002.

    I may go to a Suburban in a couple years if they get the seating arranged better and have a flat-folding 3rd row. IMHO, the current Tahoes are a bit dated.
  • dardson1dardson1 Posts: 696
    If you watch the ODY and Sienna threads (as I do), you will see these fairly heavy vehicles don't do all that much better than a Tahoe. If you factor out the 10% of ODY/Sienna drivers who claim great numbers and the other 10% that complain of low numbers. . . you land on 16/17 around town and 20/23 hwy for a green ODY/Sienna. While it's better than an un-PC Tahoe (15/19), it's about right. Moving 4300lb around with satisfying speed cost about 10% less than moving a 5000lb SUV with the same satisfying speed over the same ground. There is no free lunch. I'm old enough to remember when a big vehicle did well to do 9mpg around town and 13 driving on the road. I'm amazed how far we've come.
  • davids1davids1 Posts: 411
    For a small car, the Jetta does feel rather large. I was looking at Wranglers several years ago and a local dealer had a Jetta on their lot. I sat in it and was very surprised at the amount of room in there. The problem is that to get in the Jetta, you have to "get down there". With the Tahoe, I just slide right in without my knees popping and rattling. If I were in the market for a small car, the Jetta, or Passat TDI would be the first things I would look at. I have been lurking in the TDI discussions for some time now and have driven a few. I just can't justify the extra money, better fuel mileage and all, to trade in a perfectly good, and paid for, Tahoe.
  • sebring95sebring95 Posts: 3,238
    Oh, I'm not saying the minivan is some miraculous 4500# economy vehicle. But if you don't need 4x4 or towing you might as well spring for the better economy vehicle. Particularly when they're cheaper to buy and can have more features. We've been overall averaging 20.5mpg with the Ody, just turning 5k miles. It may have jumped up a bit here recently, but the miles have been different driving so I can't totally say it's improved. We historically averaged 16mpg with the 5.3L 4x4 Tahoe. It would turn 20-21 on all highway trips. Superb for a full-size SUV IMHO. I didn't buy the Ody for the gas mileage, but it's a nice bonus.
  • sebring95sebring95 Posts: 3,238
    Yeah, hoping I stay in good shape for sometime to come. I love driving (used to race) and while these minivan/suv/trucks are great for what they do, I'd much rather be behind the wheel of something that carves the roads a bit. I've even changed the suspension on my TDI to make it a little more aggresive, and of course bumped up the motor. Being tall, I'm used to fighting a bit to get into cars. The Jetta doesn't seem as bad because the seat goes back so far (makes the backseat worthless, but who cares) I can sit down without some acrobatic moves. The Tahoe is pretty easy to just sit into, as is our Ody. It's rarely beneficial to trade one vehicle for another just for gas mileage. Even going from 16mpg to 50mpg unless you drive a lot. I use the TDI just for business travel mainly. Instead of flying once/twice a week, I'll just take the TDI if it's within a reasonable distance (usually upto 7 hours). I've considered going to a Passat diesel, but I've got the Jetta just the way I want it and it's been trouble free for 130k miles now so I don't wanna change a good thing.
  • davids1davids1 Posts: 411
    If I ever purchase a TDI, I'll be sure to bug you on the idiosyncracies of the vehicle.

    Trying to get back on topic, I recently drove my 99 Tahoe 950 miles round trip from Huntington, WV to St. Louis, MO. I-64 from start to finish. Averaged 18 mpg, which I think is great for this particular vehicle. In comparison, just last week I took the family to Kings Island in Cincinnati, OH in the 03 Dodge Grand Caravan at an average of 19 mpg. Granted there was a lot of sitting and idling in the DGC, but I would have expected better fuel economy out of the minivan.
  • jow3jow3 Posts: 1
    My sister had the same problem and her window replaced Friday. She had to pay 800.00 at the local Chevrolet dealer. She plans to call the zone rep on Monday do you have any suggestions for her. Thanks jow3
  • bill572bill572 Posts: 10
    I have a 2002 Tahoe LT with 40,000 miles, I have owned it since it was new. When The fuel gauge reaches 1/4, the engine will not start. I have driven it until the low fuel light comes on, and it runs fine, but if the engine is shut off, it will not re start until I add a couple gallons of gas. The fuel pump comes on, and I just replaced the fuel filter, but the problem still exists. My warranty has expired, and I would like to repair it myself. Any Ideas?
  • bill572bill572 Posts: 10
    I recently heard an awful noise coming from the engine compartment when I started my engine. It lasted about 5 seconds, and then stopped. It sounded like something was hitting the fan. After reading an earler entry in this forum, I think it may be a/c related, but everything still works. I have inspected everything pretty well, and have found no damage. Any Ideas?
  • bill572bill572 Posts: 10
    Can the colored panel on the front of the outside rear view mirrors be removed from the mirror? My mirror glass is broken, and I have found a replacement mirror, but it has the black textured back. I would like to put my colored panel on the replacement mirror. Does anyone know if this is possible?
  • bill572bill572 Posts: 10
    My 2002 Tahoe has a knock when it is started. It started doing this in cold weather, but now does it almost all the time. The knock usually lasts about 20 seconds, but sometimes lasts several minutes. My oil pressure is good. I took it to the dealer where it was purchased, and they said it was piston slap, then showed me a service bulletin that addressed the noise. The service bulletin said there was no service needed, and that the noise was not a problem. The vehicle was still under the factory warranty when I took it, but the warranty has since expired. It seems to be getting worse. Now I'm no rocket scientist, but I know that when there is a knock inside an internal combustion engine, there IS a problem. I know some newer pistons don't have much of a skirt, and I am beginning to wonder if the dealership was truthful with me. I wonder what they would tell me now that my warranty has expired? Does anyone know what this is, and what I can do about it? Any help will be greatly appreciated.
  • sanandtonsanandton Posts: 342
    I had a 2003 LT Tahoe that developed the notorious "Piston Slap" around 18k miles. It was a relatively new complaint at the time, and eventually GM provided me with a letter to extend the engine warranty to 100k miles ( a program I learned about thanks to another poster here). They maintained that it was due to Carbon build up on the pistons and it did not reduce the longevity of the engine. At the time others on this board with higher mileage GM vehicles supported that stance. I ended up trading it in on an 04 Z-71 Tahoe due to some unable to be repaired Tranny problems. Interesting though that the 04 model year and newer apparently have some sort of Teflon type coating on the pistons or cylinders to reduce the chance of the start up knock. We used to call it the "cold start knock" or CSK for short. If you run a search on this thread for it, it should come up.
  • arriearrie Posts: 312
    Yes, the colored panel can be taken off. I just did it in my Tahoe when I tried to find access to inside of the mirror. My mirror bounces around guite a bit when driving highway speeds and wanted to tighten it, but could not since I could not find access to inside.

    Taking panel off does not provide access to inside. I think it only is to change the color of the back for different color vehicles.

    If you turn the mirror all the way up and right you can see between the mirror glass frame and the housing a plastic tab which you can press with a screw driver. The plastic panel has four flat tabs on it that just need to be pushed out or pulled out. I'm not sure if it is strong just to pull from the panel itself. I moved the mirror all the way to all sides to press on the tabs.

    The panel also has two sided tape around the edge of it so have some handy when you replace the panel.

  • bill572bill572 Posts: 10
    Thanks Arrie. I am glad to know this can be done. Thanks for your help. -Bill
  • jlflemmonsjlflemmons Posts: 2,242
    Check with your local windshield glass company. Many times the mirror glass can be replaced for far less than the cost of another mirror.

  • bill572bill572 Posts: 10
    Jim I did that first, but I have the heated auto dimming glass. The glass shop can install a regular mirror, but I want to keep the original features if possible. I have found a replacement mirror with all the same features as my original (except for the colored panel) for a very reasonable price. Now that I know the colored panel is removable, I should have no trouble fixing it. Thanks for your input though! -Bill
  • jlflemmonsjlflemmons Posts: 2,242

    One of those FANCY Tahoes!

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