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Chevy TrailBlazer Revs Then Stalls

I have a 2003 Chevy TB 4WD with 155,560 miles that has given me very little trouble. I replaced the alternator 4 days ago and yesterday after I got off the interstate, it began surging. I had a diagnostic done on it this morning saying that the MAP (module air pressure) sensor was bad. I bought and replaced it, but the problem remained. I had the code cleared and drove it approximately 50 miles hoping that the pc would cycle and correct the issue. This did not happen and the RPM's continue to rev and drop, even to the point of it shutting off at red lights, stop signs and during low speed braking. When driving on the interstate today, I engaged the cruise control. It maintained a steady 2100 RPM, but i could feel a control module closing and opening. I need to know if this sounds more like the TPS (throttle position sensor), the MAF (mass airflow sensor), or something else, like an Oxygen sensor?

Comments

  • kbotgakbotga Posts: 1
    Mine does the EXACT same thing. My husband changed the O2 sensor but that didn't seem to solve anything. Did you ever find the solution? I'd love to know!
  • I have a 2005 Trailblazer after installing a performance module in the IAT SENSOR it started to run really ruogh . I removed the module but it is now reving and then idling low and shutting off. ANY ONE HAVE ANY CLUE.
  • fj4072fj4072 Posts: 29
    Does this happen only when your defroster OR A/C is on? If so, clean your throttle body, will solve the problem.
  • bigdog2371bigdog2371 Posts: 1
    TPS (throttle position sensor), thats your problem
  • tdi6tdi6 Posts: 1
    I have a 02 trailblazer my wife drives. when the ac is turned on the idle fluctuates between 1000
    rpm and trying to stall and then of course stalls. I cleaned the throttle body and now it wants to idle high about 2000 rpm till it warms up and then 1000 rpm and come down slowly to about 600 rpm and idle steady. Every time I stop its 1000 rpm them slowly down to 600 rpm.
  • burdawgburdawg Posts: 1,524
    I'd check the TPS, throttle position sensor first. It's basically a variable resistor that you can check with an ohmeter.
    After that I would look at the IAC valve, many times an erratic idle is caused by a gummed up sticking one.
  • I have a 05 ext/ls, ocasionaly (2 or 3 time a day) when coming to a complete stop the engine starts to idle very low and rumble and if I don't press the gas peddle it stalls. If I catch it before it stalls and press the gas peddle it hesitates alot before it feels like it gets fuel and the rpms raise. But while moving it runs fine. The check engine light is on and its codes read- fan clutch, fan clutch switch, and o2 sensor. The gas cap light comes on every now and then and feels like it doesn't seal completely closed. Also the 5th speed on my ac unit switch doesn't work but 1-4 do. The rear speakers of the stereo are in and out, usually out. The door ajar and seatbelt chimes are also in and out along with the rear speakers.

    PLEASE HELP
  • I had the same problem. It was like that for a year. I just fixed by cleaning the throttle body. It wasn't hard. I Google it and and found this link. Made it so easy! http://forums.trailvoy.com/showthread.php?t=51619

    Hope it helps you too!

    Step by step instructions and pictures to help.
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