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Chevy Silverado and GMC Sierra Gasoline Engine Problems



  • Here's the deal, a couple weeks ago my 2008 Silverado with 60,000 miles decided to blow - or more appropriately, decided to drop a valve 4 hours from home. It lost all power, started throwing messages, started ticking (obviously the piston slapping the valve) and started smoking white smoke.

    So under warranty, they towed my vehicle and replaced the engine. I got the special treatment of getting a 99 Lumina to drive! I picked it up several days later (on a Friday) with a new engine and headed home. All was fine for about 30 miles. Then the emissions light came on. I pulled into a parts store and had them scan my codes - P0171 and P0174 - right and left banks lean. I had them reset the codes, thinking it was a glitch with the new engine...30 or so miles later, got the code again.

    I called the dealer Monday and explained the issue, to which they told me, "that's an emissions issue, unrelated to the engine and not under warranty"!!!!!!!!!

    So I reset it again...and again it came on. Then I drove it about 100 miles and it went off...then another 30 or so and it came back on....

    Since clearly I wasn't going to get any satisfaction from the dealer (4 hours away), I decided to call Warranty customer service...explained the issue, started getting the "it's an emissions problem not covered". I asked to speak to a supervisor that couldn't be found, was told one would call me back...waited for 4 hours...and had the original person call me back.....

    "Sir, I spoke to the dealership service department and they said it wasn't related to the engine" UGGGGGGGGGGGHHHHHHHHHHHHHHH

    Long story short...Ms Customer service explained over and over and over that an O2 sensor is "different" from the engine...she couldn't understand how a trashed valve, or heavy smoke, could have damaged/fouled an O2 sensor!!!!!!

    So..once I get this fixed on my dime, I'm trading the POS in...I guess there's a reason FORD is the #1 selling truck...I just wish I had listened to the ads...and wish my tax dollars hadn't been part of GM's bailout since it's going to be short lived!

    Sorry for my rant...I've loved this truck...but the "Customer Service" blows!
  • wmazwmaz Posts: 3
    There are horror stories like yours with every major auto manufacturer. I've had problems with all of them. Chevy, Ford, Dodge, and finally Toyota. Getting a good truck is a crap shoot. My last new truck was a 2006 GMC Sierra. I wish I would have kept it, it was a lease. Sucks that you got stuck with a lemon but don't think that Ford will treat you any different. Good luck with your next purchase. By the way, you are going to loose your [non-permissible content removed] trading that truck in. Been there, done that!
  • madmuddermadmudder Posts: 4
    I am looking for info on swapping my 454 tbi out of my new body style 88 chevy truck. i am wanting to put a 350 carb motor in it while i am overhauling my 454.
    The truck has a 454 with 400 trans and the 454 looks like the same as a carb but with a tbi adapter. Did they do this in factory ? If anyone can help i would appreciate any info
  • I guess my issue isn't so much with the engine failure as it is with the "after-care" from the dealership and customer service. I work for a major diesel engine manufacturer and despite our best efforts, defects happen. But we take a failure in the field VERY seriously - and jump through hoops to ensure the customer is satisfied and made whole.
  • corkscrewcorkscrew Posts: 254
    This link may help you with codes P0171 and P0174:
    Oxygen sensors tend to diminish with age as contamanants accumulate on the tip and reduce their ability to produce voltage.With 60k on the odometer and white smoke coming out of the exhaust, I can see an O2 sensor fouling. You can check a sensor with a digital storage oscilloscope (best way) or digital voltmeter.
    Start by cleaning the MAF sensor and check for a vacuum leak.
  • cowgirl37cowgirl37 Posts: 1
    I have a 2000 gmc 2500 misfiring on 2,4,6 but only when you first start in after 10 mins runs fine and will not show or store a code. what fixed your truck maybe its the same problem thanks
  • 1998lincoln1998lincoln Posts: 108
    check the engine temperature sensor! If it's failing it's telling the throttle positioning sensor that the motor is cold so it keep's dumping a lot of fuel. So when the gas is pushed it will flood and it will die! Just something to check ! Good Luck.
  • So...after getting NOWHERE with "customer service" based out of India and Mexico, it became obvious I would have to seek my own repairs on the new engine.

    Long story short...without thousands of dollars worth of diagnostic equipment, it's hard to determine whether sensors are working right or not. I started by having a neighbor take it in to the local dealership he works for - he got the codes scanned which came up as the same p0171 and p0174 ---but the dealership didn't want to get in the middle of the "argument" and get involved. Using an inexpensive scanner and a multimeter, I started looking at freeze frame data (couldn't see live data) and working though the troubleshooting tree outlined in a Mitchell manual. This isn't ideal - the data is incomplete at best and leads down false roads, but it's all I had.

    I tried to locate an intake leak using propane, but couldn't get a rev....

    First thing replaced - O2 sensors. No luck, just $320 and a 90 mile round trip drive to get the parts.

    2nd thing replaced - MAF sensor. No Luck, another $170 and another 90 mile round trip for parts.

    3rd thing replaced - MAP sensor. Again no luck, a days wait for the part and another $70.

    At this point, started looking for other problems. I didn't have a fuel pressure gauge, but now I do $50 later. No luck (a good solid 60 psi)

    Took a look at the throttle body - a fair amount of residue. Decided to remove it to clean well. While removing a nut off of one of the studs, the stud broke as soon as I went to loosen it. I thought "AH HA!" - figured the flunky had over-torqued the throttle body and it was sucking air. A drive to the local parts stores, then an ACE hardware, I finally came up with a suitable 6 mm bolt to replace the stud.

    Guess luck.

    So...I call my neighbor at the local dealership...explain I've run out of options, replaced or checked everything that could have been a factor...and still no solution. At this point, I willing to pay for it to be smoke tested. I take it in, tested, and guess what: #6 cylinder intake gasket leaking!!!!!!!!!

    In all of my emails and conversations with "customer service", I explained that the Lean Bank on both sides of the engine was very likely intake leaks from the engine assembly at the dealership....a point they continually dismissed as "it's an emissions problem".

    So here I am - $610 in receipts for parts plus 180 miles in driving, 5 days of working on it, looking for parts, researching, etc....and 3 days late for going on vacation (it's a camping vacation and camping at a music festival, all paid for - but I need the truck to haul gear from NC to WNY), waiting on the dealership to get the intake gasket and get it reassembled. Oh, let's not forget the couple hundred miles driving to see if the codes would reset!

    One more thing - the local dealer is fighting to get the repair covered since it was due to faulty installation by the out of town dealership 3 weeks ago, but by "Warranty" standards, gaskets are not covered! LOL

    I suppose it's going to be lawyer time - I doubt I can get Bruce in India or Tom in Mexico to understand any of this....
  • Hi everyone,
    I have an issue with '97 GMC with 225,000mi. It started a while ago with a P0300 that would occur intermittently. Then it started to get worse and the truck would shake, like it was cutting out. Currently it will start fine, warm up and then backfire when under light load at lower speed, high-speed cruising (mostly when being very light on the gas - kind or when you back out of it, then it will pop-pop-pop), or when I get off the gas when I reach speed. The truck performs pretty well when I get on it, relatively no hesitation and she has power.

    I changed out the plugs, wires, cap, O2 sensors (upstream), transmission and converter, knock sensor, MAP, motor mounts, intake, exhaust, EGR valve, Evap Purge solenoid, and some more that I know i'm forgetting.

    Bottom line - it's getting worse. I'm thinking it could be a PCM issue or another sensor that feeds the PCM values, because the truck will start and run fine until it warms up, after it goes "closed loop" the problems start kicking in. Another anomaly is that the truck will accelerate fine, that tells me the fuel pump is working well right?

    I'm an active duty Marine and don't have a ton of money to throw at the issue. I decided to take it in the pants and brought it to the dealership here in DC. They kept it for nearly two weeks, never called me or returned my calls and so I went and got the truck back without any diagnosis. I can't afford to be without the vehicle for that long- or suck up the 120 an hour the dealer charges. Any help from you all is greatly appreciated. Thanks in advance for your response!

    Semper Fidelis -
  • 1998lincoln1998lincoln Posts: 108
    Just something to look at1994 silverado dies when put in gear and push the accelerator. Otherwise runs fine, it is a 5.7L vortec . Have changed almost everything (complete tuneup} plus the throttle possession sensor. The funny thing is that is the code it is reading. I have put 2 new ones on it, checked all the wiring and plugs to it. I have one person telling me it could be the MAS or the pick up coil. Any ideas?

    Additional Details
    WELL, we got it! Who knew.. It was the engine temperature sensor! It was failing so it was telling the throttle positioning sensor that the motor was cold so it kept dumping allot if fuel. So when the gas was pushed it flooded it and it would die! Problem solved!!
    6 days ago
  • wmazwmaz Posts: 3
    I would suggest you find a repair shop that has a good scanning tool, like a snapon. They will be able to tell you which cylinders are misfiring. The code should tell you but a P0300 is random misfire. I had a similar problem and had to replace the PCM. Turned out the connections for the fuel injectors were firing at the wrong time. The terminals were right next to one another. If your Check Engine light is flashing you are doing damage to your converters. Don't drive any more than you have to.
  • Thanks wmaz, The Check Engine light hasn't came on in a long time. Normally it will vibrate and then the light will come on without flashing. I'm looking into getting a new PCU from a salvage yard. Crossing my fingers it helps. Thanks again.
  • hi all...guess ill start from3 days ago..3 days ago, while driving to work, truck spitted and sputtered then quit. revved it for about 15 min..all was fine..after driving 6 more minutes down the road does the same thing, but does not crank back up..i have it pulled to my home.put the diagnostic on it and got codes po171 & po174..replaced the bank 2 /sensor 2 o2 sensor and fuel filter. cranks right up and runs. now idling rough and wanting to stall out.check..ran diagnostic again over 10 times over last 2 days and getting 0 codes, but still really cannot drive it until the rough idiling and the wanting to stall issue is fixed....any thoughts or suggestions?
  • diagnostic test shows misfire on 2,4,& 6 changed plugs wires, rotor ,and cap running worse than when i brought it in it idles rough boggs down revs between 2&3 and barely moves removed three of the plugs that i just replaced and they were black pistons sound off like they r goin to shoot through the block mechanic spent eight hours on it and has been stumped he smelled the exhaust and says it smells like its dumping fouled gas what ever that means did it by bad gas did somebody dump something in my tank or is there a different solution
  • i have a 2000 chevy tahoe and a had the same problem just go to any auto parts and buy a throtle body cleaner remove your intake hose and spray it real good in your throtle body, and it will take care of the problem.
  • lfeleslfeles Posts: 2
    Mine started when I changed to synthetic oil. Was my first oil change. They should extend our warranties on this engine.
  • just_truckin13just_truckin13 Posts: 3
    edited October 2010
    2006 GMC Sierra 1500 SLE 5.3L V8 Vortec - 1st owner
    -I feel a rough idle while in park or stopped during travel. new plugs and wires, new air filter, cleaned throttle body and added fuel injector cleaner.

    -I'm unable to locate a PCV or EGR valve. I've been told that my particular vehicle does not have a PCV valve.

    -Suggestion? Advice?
  • obyoneobyone Posts: 8,054
    Clean or replace your idle air controller.
  • Unfortunately my sierra is a later model which does not have a IAC. Thank you for the reply
  • hi i have a 2000 silverado 4.3 just replaced intake manifold gaskets,and now its not firing on number 5,got new plugs and leads swaped number 3 injector to number 5 pulled plug lead off 3 and engine noise changed pulled lead off 5 no change,had compression test on 3 and 5 both same reading ,got good spark ,never replaced intake gaskets went ok but the last bolt snaped so had to take it off again and replace bolt now have this missfiring any help would be nice its hard to find as im in uk thank you
  • I've got a '99 silverado 1500, and it runs very irradic. under very slow acceleration it's fine but if i get on it at all it stumbles and falls on its face. Also when cruising down the road it runs fine until I start going up hill, then it starts to stumble again until i hit the gas and kick it into another gear. This truck also wants to die when i shift from R to D. This is very aggravating... :mad: It seems like the cooler the temperature gets the better this thing runs.. any help would be greatly appreciated
  • dwh4dwh4 Posts: 1
    Have 99 GMC Sierra with same problem last two winters. Changed fuel pump, filter, regulator, and MAF. Still get service engine light when cold, driven short distance, stopped and then restarted in short amount of time (less than one hour). Was thinking of changing EGR but you said that did not work. did you find fix yet?
  • I know these trucks have a problem with their "Heat Temp Sensor", it tells the computer to keep dumping fuel because the computer thinks the motor is still cold, it keep's flooding the engine! Just something to check !
  • Check your "Heat Raiser", sometimes these things will rust closed and cause this noise! The Heat Raiser is located on the exhaust manifold ! Just turn it by hand with engine cold, so you wil not get burned! If it turns or works , then not the problem and you will have to look else where !
  • truck lifters tap when first cranks up in mornin when engine warms it smoothes out until park after about a hour it does the same until engine warms then smoothes out again
  • etatetat Posts: 4
    does this problem have any todo with the catalic comverter or sensors its hard to see the atcual problem because when that happens i just turn off the truck and restart it and the error message dissappears,so i can't even put the diagnastics machine because when that happens i have to restart,do anyone have the same problem?if so what did you do about it what is the problem
  • etatetat Posts: 4
    not yet when that happens iam forced to turn off the truck and restartit so i can;t even take it to a mechanic where he can hookmit up to a dia,machine so,iam left with no answers to where to begin looking for my problem
  • etatetat Posts: 4
    my truck don;t low idle it runs great then all of sudden it slows down and the light appears that says reduce engine power then i have to turn truck off then turn it on again then the light dissappears
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