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Chevy Blazer GMC Jimmy Maintenance and Repair



  • First off, thanks for all the help from this forum. It has saved me much money from mechanics. I've got a 1990 s10 Blazer with 4.3L TBI engine. It has had a bad transmission and thus has been not running for about a year. Just got the trans. rebuilt and back in. Now, transmission works. Had to change the fuel pump/filter just before this to get it started so both are less than a month old. Took to emissions-failed. Did tune up including oil/filter, air filter, spark plugs/wires, PCV valve and oxygen sensor. Passed emissions with no problem.

    Now, it hesitates severely on acceleration. It does OK if you very slowly accelerate. Also, once it overcomes the hesitation it takes off and has no more problems until you slow down again. The hesitation occasionally produces what sounds like a quiet backfire. Hesitation is much worse when the car is warm. It doesn't really hesitate at all when it is cold. (Runs quite well until it warms up after a few minutes.)

    I've had a couple of thoughts. EGR valve or throttle position sensor? Any other thoughts about what this could be and how to proceed. Also, the Chiltons has a flow diagram to test the EGR valve. When I apply a vacuum to the EGR solenoid it does not move the EGR (also does not hold a vacuum). Next step was to ground the diagnostic test terminal, but no indication as to which terminal this is on the EGR solenoid. Anyone know?

    Thanks for your help.
  • EGR port gets clogged so unbolt it and clean it first. Any codes or SES light on.
  • Sorry, forgot to mention, no codes. I only get the 1-2 code (diag mode entered.)
  • Update: Tested the EGR today, seems to work properly. Cleaned out the ports for the EGR-had some build up, but clearing this did not fix hesitation. Checked Throttle position sensor-has good voltage change and seems to be working well.

    Any other thoughts on things to check? Thanks.
  • Is this 2wd? Check the vac lines and see if all connected and not rotted. Was the cap a Delco - seen bad aftermarket Wells caps/rotors which are sold at Autozone and Carquest. Any fuel smell would point to leaking CPI and lines (nut kit) under the intake.
  • I recently traded for this Blazer. Obviously, no owners manual. Does anybody know how to reset the drivers side power seat from moving into a different position when I unlock the vehicle? This vehicle also has a AM/FM/CD/AUX for the radio. Where can you plug in the AUX(for my MP3 player)? Is it on the back, if so will the theftlock lock it up if I partially remove the radio? I don't have the code and I don't know how to reset the code. Had the dealer reset it on my last vehicle. Appreciate any help.
  • It's a 2wd. Vacuum lines all intact. I'll have to check the rotor/cap. I didn't replace them when I changed the wires. There's no definite fuel smell, but the exhaust has a faint fuel smell to it, a little more noticeable than I'm used to.
  • This is my first time on this site-I'm hoping someone can help me. The rear hatch on my 2004 Blazer rattles and seems to leak a little bit when it rains. I was told there is a way I can adjust the hatch myself. Is that right?
  • If this is a CPI system (not TBI with the 2 spray nozzles in the top of the throttle body or carb) then look that up and it tells how to check that for leaks - common.
  • Check the top pins and weather stripping then the striker on the base has 2 torx headed bolts that do adjust. You will need the correct size torx head socket cause those are tight and a screw driver style will not do it. Sure its the hatch and not another quality part back or under there? Check that the jack inside and the spare are secure.
  • Put seat where you want then press SET and then #1 or #2 and then within 5 seconds the UNLOCK button on remote - chime will sound you are done. Can set eack remote to a diff seat position that way. If you want a manual ebay has them and remotes - match the remote code ptinted on it for correct one.
    That CD AUX switches between CD and then the radio FM-AM when a CD is in thats all. No MP3 connection so you need to buy the cheapo transmitter that goes on MP3 and tune FM to it.
  • to reset the seat, just set it to where you want it, then push the, set, #1, set, and it should be good to go. not sure about the radio as I took my radio out, shortly after I got my truck and put my sony in
  • Hello,

    My 2001 4x4 Blazer has been blowing cold air. I've replaced the already fine thermostat, and have checked the coolant and levels are fine. still making the kids wear ski pants and toques in the truck though. lol. Can someone tell me whether it would benificial to have the coolant flushed? I'm going home to check the heater dials, the heater doors and the hoses coming off the heater core (if I can find it). Any other suggestions would be so greatly appreciated.

    Signed: Cold in Canada
  • I have an odd issue and was wondering if anyone has run across this, my tail lights on one side are not working, the break lights on that side however work fine. I wish I could find a Wiring diagram to see how that circuit works however I haven't had any success. It is a 2000 Chevy Blazer 4X4, has had the Recalled switch replaced (the one that made the breaklights not work). Any thoughts or guidence to where I can find a wiring diagram would be helpful. If I can't get that then maybe someone can tell me what fuse box controls the Tail light operation and if the two sides (not the top) are different circuits and if/where they split off? And as for the obvious question, Yes I tried replacing the bulbs already :)
  • I actually had this happen to me, when it did happen it was because the Coolant had turned to sludge and plugged the Heater Core. So if you have not had the system flushed (as it says the fluid is good to 100,000 or 120,000) then most likely that could be the issue.
  • Depends on if the core is clogged - if you have never done it or had a full coolant flush/replacement that's the first step. Is the fan clutch working - after start up the noise drops off and doesn't sound like a jet taking off? Does the temp gage shows running temp around 195 after warm up? Dex cool lasts a max of 3 years so forget the GM promise of 5/100 or 5/150 cause their warranty was 3/36 - got us all on that one! Finally, have you checked that the cap is holding pressure - just buy a Stant and put it on - GM cap was junk and clogged. Hope that warms you up cause I remember -35 when my fan clutch froze and so did I in Canada one winter - love FL now!
  • gbagsgbags Posts: 2
    We have a 2001 Chevy Blazer that has begun an intermittent rough starting problem. When the problem ocurrs, the engine starts immediately as always but the idle is rough and if you try to move in reverse or drive the engine stalls. To make the vehicle move you have to give it a lot of gas pedal and hold the pedal down. If you let up on gas pedal, the vehicle stalls and completely shuts down. It seems to do this until the engine has been running for 10 to 15 minutes and then all is OK. This strange problem only happens once every 2 weeks or so at all other times the vechile starts and moves properly.

    Any ideas?
  • Could be many things, so check:
    1. fuel pressure
    2. cap/rotor/plugs/wires
    3. other electrical such as coil
    4. sensors
    5. filters gas and air
  • Hey Repairdog,
    I've been having a similar problem - no heat from only the defroster though. My blazer is a 2001 with about 82k on it and the coolant has never been flushed. The vents seem to put out heat (although its not super warm air, its definitely warmer than what comes out of the defroster). Do you think its the same problem or could it be something else? Also, if I do get the cooling system flushed, does that automatically flush the heater core as well(if that indeed is the problem) ?

  • Could be and yes flush that out and put a new thermostat and Stant cap on. Sometimesa chemical flush will actually create a leak in the core or the crap gets in the water pump seals and that goes. The 4.3s have a weak lower intake gasket that most find leaking by 100k. I separately use two 3 foot sections of heater hose 5/8 and 3/4" to do the core with a garden hose and hold it to them with my hand to limit pressure and do in both directions till runs freely and clean. With too much Dex cool in the system a voltage diff of a few tenths volts can occur in the fliud and eats the core and radiator especially if the grounds are bad.
  • So here's the latest. I changed the rotor and cap (both needed it) and the fuel filter again. Then, the blazer failed to start at all. I found that it had a bad ignition coil. After changing this it fired right up and now seems not to hesitate (although I haven't really given it a solid test drive yet.)

    Would an ignition coil in the process of failing cause a hesitation on acceleration (especially around 20-30mph when accelerating at any speed more than a crawl)? Or... is it likely that I'll still be dealing with the hesitation issue in the future?

    Thanks for all the help.
  • I started by flushing the heater core per your suggestion and it fixed the problem. It was easy and the heat works great now. I will probably still follow through with your suggestion of flushing the whole system and replacing the the cap as well. I was surprised however how little "sludge" came out. There was just a little browish-pink water then it ran clean. It definitely fixed the problem though.

    Thanks Repairdog!!
  • I have a 2000 Blazer in the shop right now and it has been there for a week. The tech does not seem to be able to find the problem. It will run fine then it will stall. The engine does not hesitate before it stalls or give any indication that it is about to stall. I stalls both when idling, and when driving down the street. After it stalls it starts right back up as if nothing was wrong. The engine light does not stay on. I have changed the fuel pump, fuel filter, spark plug wires, had the injectors cleaned. The tech claims that everything checks normal on the diagnostic machine but then the engine stalls. He is not getting any codes. Any ideas?
  • This at a GM dealer - if not might want to do that. Could be many things as easy as a defective cap/rotor if an aftermarket one - change with a Delco to rule out. Assume coil was tested and with a scan tool all sensors can be looked at. Possible crank sensor failing but dealer can pinpoint.
  • I am also having this problem. When ever I turn the heat to go to the floor it blows out the windshield defrost. All other settings work fine. Please help!
  • hi can anyone help me i have a 1986 s10 blazer 4wd 2.8lt
    and i just put a fuel pump and a fuel line filter in it and when i start it up after i get about 2 miles down the road it stops and when i go to mash the gas pedal it wont do anything the engine wont even rev and then it will eventually cut off and about a hour later u can crank it back up and it will do the same thing does anyone now what it could be
  • Possible choke cutting off air, sensor, coil heating up. That baby is 20 years old.
  • Thanks for all the great help. I had the system flushed (decided against the 50/50 chance of all those leaks from a chemical flush) and its blowing more heat than I can stand.


    signed: Now warm in Canada.
  • hey i have a 1994 GMC Jimmy and i replaced the fuel pump, fuel filter, spark plugs, and spark plug wires and now its not getting fuel to the engine the pump works and i got 60psi of fuel and the check velve but car still won't start and it has spark but still won't start what could it be please i have to get this car fixed A.S.A.P is it the CPI, ECM, what? :sick: :confuse: :mad: :cry:
  • Cap and rotor next. Wires in right firing order? CPI you smell gas.
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