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Chevrolet Blazer Engine and Performance Problems

tidestertidester Posts: 10,059
I am consolidating many of the topics that deal with engine related issues and engine performance.

tidester, host
SUVs and Smart Shopper


  • Hello,
    I have a 1998 Chevy Blazer. The Idle is fine, the acceleration is fine.
    But when you get it up to a steady speed it Misfires.
    I have changed spark plugs, and plug wires. Replaced the fuel filter.
    Ran injector cleaner time and time again.

    I don't know what else to do. Can you PLEASE help me?
  • tidestertidester Posts: 10,059
    You'll have a far better chance of getting help if you post your message where other Blazer owner's will read it. You can find them here: Chevy Blazer/GMC Jimmy: Problems & Solutions

    tidester, host
  • aallen2aallen2 Posts: 5
    My blazer is a standard shift where the motor reves when I go to switch gears. What could this be and about how much is it to fix?
  • tidestertidester Posts: 10,059
    I don't think it will cost you anything! All you need to do is lighten up on the gas pedal when you're pressing the clutch pedal.

    tidester, host
  • aallen2aallen2 Posts: 5
    The engine is doing the revving on its own every time I push in on the clutch. It looks like the clutch has gone out. It has 120k miles on it. Is that the normal life for a clutch?
  • blaze4x4blaze4x4 Posts: 29
    Clutches, like brakes and tires are a wear item... Much of the life is going to depend on how they are used (or abused). Personnally, I think 120k is pretty decent distance on a clutch. As for the revving, check the throttle cable. Sounds like it's sticking either bunched up floor mat, or broken spring at the throttle body.
  • repairdogrepairdog Posts: 948
    Clean the throttle body with some carb cleaner and a toothbrush - probably gummed up on the butterfly or throttle valve. See if thst does it first. Check the vac lines too.
  • aallen2aallen2 Posts: 5
    Excuse my ignorance, where is the throttle body located and is it something simple enough for me to handle on my own?
  • repairdogrepairdog Posts: 948
    Its the thing that the air goes thru (like the old carb) but no fuel - yours is injected so fuel cleaner never goes thru it. Remove the tall screw on the back of the air housing center of engine, remove the pipe at the rubber grommet, tilt the black plastic housing up to unclip it on the front edge and lift off. Now you see the throttle body and with eye protection on you spray carb cleaner in and hold the throttle open and use a toothbrush to clean it so all black gunk is gone. Replace all things and start - may shake for a few seconds till the cleaner burns off.
  • North bound from Niagara Falls NY to Toronto today. Lost all throttle at 90 mph. The truck remained on and everthing was fine however when I hit 90 mph it felt as if I'd hit a govenor. As the truck slowed below the speed the accelerator seemed to kick in again. I tried after a while to reach 90 mph again and at the same speed and this event was repeated. I purchased this 2002 ZR2 this year from the original owner. I spoke w/ her today and she stated she seldom drove over 70 - 80 mph and never experienced what I described. Wondering if anyone is aware of this.

  • Computer programmed at approx 93 to limit you - have to buy an aftermarket programmer to alter. With a ZR2 4wd I'd avoid those speeds from the standpoint of your drivetrain and transfer case - lots of Extremes get altered but 2wd.
  • It has a speed limiter as do all newer vehicles (at least GM). Newer vehicles also have "little black boxes" similar to that of an aircraft that record data, such as rate of speed and law enforcement can (and have)extract that information should the need arise, from say an accident.
  • Thanks for your reply. Did'nt know of this information. I'll leave it at the factory specs. Much appreciated. Just seems this truck could ride along at a high rate no problem. Very comfortable to cruise in.

  • Can anyone tell me if my 1995 4.3L S10 Blazer Vin W has a MAF and is so where is it located. I have looked and do not see what I generally recognize as a MAF.
    Thanks David
  • None on 95 - started on 96up with newer injection.
    You have a MAP sensor or mass air pressure on the manifold.
  • Thank you and does the MAP sensor need cleaning like the MAF?
  • poof1poof1 Posts: 3
    so how crazy am i to want to put a 4.3 engine and tranny into my 86 S10 blazer that has a 2.8 in it ?
  • repairdogrepairdog Posts: 948
    Depending on what year 4.3 and trans you will need the computer and wiring to make it work. The 4L60 is electronically shifted and the 4.3 and many sensors including the 3 exhaust O2 ones all are required or it will run like crap if at all. Why not go for a real engine and put a 350 V8 in with a 700R4 trans - can be done but not in a smog check/inspection state so check state laws first. As to the 20 year old Blazer have to ask why do you want the headache cause you can pick up a 96up with the newer injection (98up added rear discs and better airbags) for pretty cheap with higher mileage and rebuild them and its way easier. For real 4wd get the older solid front axle full size Blazer with the 350 and go from there - so many parts out there and more room to work on. You can beat the crap out of those - wish I had my 89 Suburban back but rust caught up.
  • poof1poof1 Posts: 3
    Luck has it I have everything, puter, wiring, sensors, saved the 350/700r4 for my 88 3/4 ton, ( it's a 40 over stroker) but this old S 10 has a soft spot in this girls heart. Any way the body has no cancer and is in really good shape.
  • Hi i had the same problem with my truck then it started poping codes saying a muti port misfire. I went to a shop. They told me it was my injectors. I did not think that was right so i tried acouple of things. There is a controll module in the distributer it cost about 40 dollers and after i changed that the problem went away. But the damege was done it fried my cat I cant remember what the part was called. But you can ask your local parts store. P.S my motor is a 4.3 L v6 with the delpi system.
    Anyway good luck hope it helps.
  • repairdogrepairdog Posts: 948
    Must have been the cam position sensor in the distributor. Ignition module is mounted on the coil on newer models. The random misfire P0300 can be injectors, cap/rotor, coil, ign mod, vac leak, and a few others so this is way a good dealer scan can save you money - if they can actually spot the cause - some never pop a code and only occur at certain throttle conditions. Mine was a crank sensor that threw timing off so at full throttle leaned the fuel mix out and misfires in all cylinders. So a lean mixture due to failing fuel pump can also cause this. Good you found it.
  • Color me unlucky ( I wasn't really stupid was I- no answer required on that )

    My 86 S-15 Jimmy ( 1992 engine )311,000 miles, 2.8, started having a slow idle and stalling( ran fine) so I figured I would find the vacuum leak with starting fluid. Found it,(vacuum fittings on air cleaner) idle came up so I turned it off and walked away to find a small fire by the fire wall when I came back a few minutes later.

    It could have been worse. The coil and electrical connectors on them were partly melted along with the insulation on the wires going to the connectors ( but they are identifible by going back a few inches) and the distributer cap melted up one post.

    What is that box mounted with the coil with what looks like heat fins on it?

    I will go to the Junk yard an get a coil ( I need the connectors on top too) along with that box I can't identify ) replace the distributer cap and then I am stuck.

    Maybe I will get lucky and find the vacuum hoses and fittings also but I have the feeling that without something showing me where all the vacuum lines come from and go I am going to be in trouble. I ordered a Chilton Manuel maybe they will have a diagram.

    Any ideas for someone who is kind of a parts replacer rather than a mechanic?

    I am also posting as a Public Service Announcement that ether ( starting fluid ) can take some time to ignite so don't walk away soon.
  • Sounds like the ignition module (1x2" IC pack). Good luck. You can buy new connectors at many stores.
  • My 99 S-10 Blazer engine missfires (4.3liter tbi) when cold but runs great when warmed up. One shop said this is caused by the ECM. No codes showing and all sensors checked good. Milage is 204,000+ Please help!!
  • I am trying to pull the module inside the distributor. The problem is when i took the rotor out the module is under something metal. Do I have to remove the whole distributor to remove it or is there something I am missing.
  • Did you have to pull the whole distibutor. If not how do you get the module from under the metal piece? I pulled the rotor and the piece is directly under it. I removed the screws in the module but it wont slip out
  • The cam sensor has 2 torque screws that hold it in BUT the dist position only allows 1 spot where the sensor clears that rotating asembly so you can bump the starter till it lines up or remove the dist. This is 96up so if older model and its the ignition module thats a diff story.
  • same as other posts answer.
  • Could be lots of things at that mileage. Fuel pressure needs to be 60psi for cold start so that is one to check first and thats usually the pump in the tank. Then on to a full tuneup with cap/rotor, plugs, wires, fuel filter, air, PCV, clean MAF sensor, etc you get the picture. Then possible wiring or sensor, connector, etc.
  • We just bought a 96 Blazer... The 4 wheel drive is not working... It sounds like it is trying to click in but doesnt... There are 3 Vac lines on the transfer case that are not hooked up... I don't know where these go.... Can anybody help
  • repairdogrepairdog Posts: 948
    I hope they are still hooked to the formed rubber connector that snaps over the transfer case 3 port switch - if so on the NP233 3 button case on the drivers side halfway down thats the 3 port switch - clip it back on it only goes on one way with the keyed post. One is the vac from the engine, one is the line to the front actuator, the third is a vent line to the front act and transfer case. If the 3 port switch is bad its $15 Motormite #49315 at most auto stores and takes a 7/8" box end to replace. If all lines separated and no rubber connector then reply and I'll explain what goes to what.
  • There is no Vac coming from box on intake... Does it come from Transfer case?? Does the Vac come from another place... I cant seem to find vac anywhere... The Lines are connected to the transfer case with the 3 port connector then they go to the front of transmission and then they got burned.... So I don't know where to go from there... Thank You.....
  • repairdogrepairdog Posts: 948
    OK here we go.
    1. Vac comes from underhood drivers side. Follow the vac line 5/32" from by the valve cover PCV over to the drivers side and replace rotted lines (all are) and to a vac reservior can in the fender (yes you can feel to put a new line on) and one Ts off to run down to the 3 port and the final plastic at the end is for the heater controls.
    2. On the 3 port rubber connector if you look inside it you will see 3 holes/lines and a keyed position hole. With the keyed hole at the bottom of your view there are 2 lines above one on left is the VENT line one on right the VAC line from the engine. Then the third line at the peak of the triangle is to the front ACTUATOR line.
    3. Straight lines from the vac and to the actuator. But that vent line is T to a transfer case vent line and then should run up the transmission dip stick secured by a tie and has a vent cap on it.
    4. Another check is to look at the 3 port switch which then has 3 plastic line tubes/connectore and a fixed plastic pole as the keyed position (of the rubber to line up). Looking down on the top of this 3 port switch the vac is on the left, the vent on the right, and the top of the triangle line is the actuator.
    Thats it - take your time and it should work. I would change that switch anyway while under there so if any problems rules that out up front.
  • jlflemmonsjlflemmons Posts: 2,242
    Okay, so you have gone through a case of belt dressing, changed both idler pulleys, and that blasted new Gates belt still starts chirping again within miles.

    I couldn't believe it when a mechie showed me what it was. Are you ready?

    It's the painted on Gates logo and part number. When the label goes by the top idler pulley (it is running on the back side of the belt, remember)the paint used on the label makes a distinctive "chirp". The label is painted in two different spots on the belt. I took a little silicon grease and rubbed it on one of the labels and, sure enough, only got the chirp half as often per belt rotation. Rubbed the grease on the other label and the noise disappeared completely.

    The mechie said with time the noise will go away on its own, but that he had seen this on numerous belts. Treating with belt dressing will help for a while, but the dressing doesn't stick to the painted label, so once is cleans off, back comes the chirp.

    Durndest thing I have seen in a long time.
  • tidestertidester Posts: 10,059
    Thank you - that's one sharp mechanic!

    tidester, host
    SUVs and Smart Shopper
  • 53jinx53jinx Posts: 6
    I just inherited a 1992 Plymouth Sundance. Since the day I got it I’ve been fighting a squeaky belt to my alternator. After messing with the tension I had it down to a tolerable level. However, after using some stop leak for my radiator, some of the fluid come out of the over flow dump and landed on the belt and the squeak was back. I decided to give belt dressing a shot. That was a mistake. It only got worse. I tried adjusting the tension some more, however it didn’t help.

    I decided to switch out belts. I read through the forums and based on others recommendations for noisy belts I decided to go with the Goodyear Gatorback or a Gates belt. I went to Pep Boys, and they didn’t have either. So I went to Napa and they pulled a “Napa” belt off the shelf. I was about to walk out when the guy showed me on the back of the label that Gates made their “Napa” label belt. I decided to give it a shot. I replaced the belt and the noise was cut by about 2/3, but still there. Then I read your blurb about the Silicone Grease on the label, and it worked like a charm. The only silicone grease I could find was “Danco Silicone Faucet Grease” at Home Depot, but it worked. Thanks for the advice!!
  • jlflemmonsjlflemmons Posts: 2,242
    Glad to help. It has to be one of the oddest noise producers I have ever seen.

  • steverstever Posts: 52,457
    I love solutions like this. You should write up a CarSpace Guide about it so the cure will get even more Google hits.
  • sbalsanosbalsano Posts: 5
    Back in march the dealer repaired coolant leak from intake,replacing lower manifold and gasket. they also performed complete cooling system flush, 10 days later had to have it towed back because it started to blow hot from the a/c and temp gauge reading over heat.the dealer said i blew upper rad. hose,they replaced that. 6 weeks later same problem, this time i let it rest about 4 hours checked for leaks, it cooled and drove fine. i took it to another gm dealer, they could not find a thing wrong, they did pressure tests found no leaks, changed the thermostat just in case. now 10 days later same problem, i never had this before the first dealer visit. any ideas?
  • tidestertidester Posts: 10,059
    It doesn't sound like quite the same problem but you may want to check this out: No Heat And Overheating

    tidester, host
    SUVs and Smart Shopper
  • repairdogrepairdog Posts: 948
    You said a new thermostat but did you get a new radiator cap - the GM ones can clog and not work and the advised fix is buy a Stant one - when these clog expanding coolant cannot go into the overflow tank and then when cools be sucked back to rad or do not hold the 16lbs pressure so coolant boils at lower temp. 50% mix in coolant. Then also possible the radiator has many of the small tubes clogged that run thru it as the flush sometimes pulls the crap out of the heater core and block and it can then clog the radiator. Next would be water pump but said no leaks. Then fan clutch going. Is AC compressor good and not a big rpm drop or drag. The final thing that could cause is a leaking heat gasket if you got the engine really hot before the intake job and they can be pinhole size that reseal and only blow open at higher temps (with AC on) and dealer can pull plugs and look and run a compression test if it comes to that but these motors don't normally do this.

    For all - 3/36 or 3/50 on coolant change do not believe the Dex Cool 5/100 crap. At same time always a new thermostat and Stant cap.
  • can you clean the mas air flow sensor or dose it have to be replaced when bad ?
    thank you
  • repairdogrepairdog Posts: 948
    If the wires or actual resistor embedded are damaged it has to be replaced but if only dirty take it out and spray off with MAF spray, electronic cleaner, or even brake cleaner but NOT carb that leaves residue. Keep a clean air filter in there too. Many MAFs get oil from an over oiled K&N filter.
  • Ok thank you
    i am thinking that is is a problem that is acuring becouse it was brining up a code and they checked it when they replaced the sylnoid and tranmission computer i still get a little hesitation so i am going to try and replace or clean this out first and if it dosnt help then take the car back to the shop on monday and get looked at agen
  • poof1poof1 Posts: 3
  • I did a similar swap into a 97 4x4 blazer and then drove it about 150,000 miles with no trouble the biggest hassle I had was integrating the original dash cluster if I were going to do it again I would find a later cluster and harness/ecm from a 4.3 blazer in a boneyard and it will just be a plug and play situation. Performance was great and it passed emissions in Illinois. Sadly rust took ove.Good luck
  • delk77delk77 Posts: 1
    I have an 01 Chevy Blazer. After I went muddin I went to the local watering hole to cool off with some suds and when I left the truck wouldnt start. It's definatley the starter. I removed the 2 bolts and the starter is loose but I cant remove the 2 wires or get the starter out. I need about an extra 1/4 inch of space. I also tried to remove it through the half flap in the wheel well with no joy. Can anyone tell me how to remove it soI can take it apart and clean it or replace it if I need to? I'm so lost.
  • repairdogrepairdog Posts: 948
    The 4wd is a pain and after disconnecting the positive battery cable at the battery, as you did remove the 2 main starter bolts, then curse as you need 1/4" drive with extension and socket to get to the solenoid nut and then 3/8" drive for the positive cable nut both as the starter is angled at 45 degrees or so to manuever the sockets. Then when that fun is done the starter must be flipped 180 to get it to drop out the bottom rear - yes it just fits. Some jack the pass side of the motor up alittle but that can split the brittle rubber in the motor mount and those are a real pain to replace, drivers side worse.
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