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1994 GMC 1500 5.7L - engine hesitation and stalling

Discussion in 'Chevy C/K Truck Forum' started by love.the.smell, Sep 21, 2013.

  1. love.the.smell

    love.the.smell New Member

    Thanks in advance for any help!

    I'm new here but I've been tinkering on my own vehicles for quite a while now but I'm not real comfortable with the 'newer' stuff that has all of those electronic gizwhatzits.

    Like the title says, I've got a '94 GMC half ton truck, 2WD, 5.7L engine, 173K miles

    Often (but not always) when I start the engine it will run rough and act like it wants to die - increasing the throttle a bit helps it stay running. On really hot days this summer the engine might die several times before it stays running. Now that the weather is cooler it just idles rough sometimes.

    Acceleration from a stop is very poor. The engine hesitates and sort of coughs causing the truck to lurch and doesn't run smoothly but at higher rpm it seems to run well.

    I've done a little digging on these forums and found an entire laundry list of what might be the problem. I guess first I'll check out that TPS and make sure it is working correctly.

    I was going to install new spark plugs and wires but it seems that might not even be part of the problem.

    Any suggestion would be greatly appreciated.

    Thanks!!
  2. Jonezee

    Jonezee New Member

    As far as the stalling issue goes, is the exhaust system ok? No leaks? My dad has an 89 GMC K1500 4.3 and. it kept stalling whenever he stopped at a light or stop sign, it had an exhaust leak and when that got fixed the problem went away.
  3. Crispyt

    Crispyt Rockstar 100 Posts

    Its possable that the temp. sensor could be bad giving the ecm a bad temp reading. This could cause either to much fuel going in or to little. The first thing to do is make sure that your getting enough fuel pressure first. (test after fuel filter).


    Always trouble shoot like this...

    Fuel-----> Ignition-----> Compression

    So make sure that your getting the right amount of fuel pressure with the key on engine off. (KOEO) If you are make sure that you dont have a leaking fuel injector. You can take the air cleaner assembly off so that you see the two injectors. Next turn the key on but only enough so that your fuel pump turns on. Have someone look to see if one of the injectors starts to drip a little bit. If it does replace it. After checking the fuel system make sure that your getting a good spark and that its timed correctly. Its possable that if you have bad spark plugs and wires it could cause this to happen. Lastly you should make sure that you have good compression in all your cylinders.


    It's possable that a bad TPS can cause problems like this. You will need to unplug it and and do a resistance check on it as you move it from idle to full throttle you need to see if its an even increase in resistance and that its at the right spec at idle and full throttle.

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