94 chevy k1500 4x4 5.7 tbi sputters when warm

Discussion in 'Chevy Truck Forum' started by johnri01, Apr 22, 2011.

  1. johnri01

    johnri01 New Member

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    Truck starts and idles fine. Drive it down the road and when it warms up it starts loosing power like lack of fuel. I can punch it and it takes right off. As rpms go down ( cruise speed) it looses power, sometimes sputter and acts like it chokes. Took to mechanic and he said it needs an 02 sensor, map sensor , egr , and gasket under carboratour. All that has been done and it still does it. I also changed the fuel filter, plugs, plug wires for good measure. It doesn't do it all the time but lately it has become frequent and expensive. Any suggestions? I can stop at lights and it idles smooth.
     
  2. zombie1969

    zombie1969 Senior Member

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    Sounds like a lot of guesswork going on there.You can check the fuel pressure while driving and have a vacume guage also to check for a cloged cat or just disconect the cat and drive it with open exaust to see how it runs.
     
  3. johnri01

    johnri01 New Member

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    it does the same thing with the cat disconnected. My next guess is could it be a TPS?
     
  4. zombie1969

    zombie1969 Senior Member

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    You can check the tps with a volt meter.After the meter is conected to the signal wire just move it slow and watch for glitching.You can pull the dizzy and inspect the gear for wear and replace if needed.Check for shaft wobble also and the pickup coils have gotten damaged from moisture getting traped inside the cap also.
     
  5. johnri01

    johnri01 New Member

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    Thanks for the info, but what is a dizzy? Are you referring to the distributer? If I unplug the tps the motor runs smooth, but when i hook it back up it fluxuates again. If I hold truck at 2000 rpm the rpms start to pulse up and down. It will run smooth then it will act like it wants to die then it picks right back up again , pulses , runs smooth... nothing truly consistant as it will also run smooth until motor heats up.
     
  6. johnri01

    johnri01 New Member

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    94 chevy 4x4 truck sputtering 5.7 350

    The Mechanic said truck needed an O2 Sensor, and MAP sensor and a throttle body gasket. Ok, that was all replaced. Then I replaced the throttle sensor, fuel filter and it has new plugs and plug wires. I am at a loss of what else it could be. The intake is not sucking air either. It starts and idles fine but when you drive it sputters then goes, then may drive fine for a few minutes then it will do it all over again. I can let of the gas a bit then step on it, it will go in to passing gear and take off ( as if i were passing another car) but then it will sputter or jerk again. Any more suggestions??? PLEASE??? :confused:
     

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