2001 suburban 4 by 4 5.3 motor

Discussion in 'General Chevy & GM Tech Questions' started by japsmash2001, Dec 29, 2009.

  1. japsmash2001

    japsmash2001 Member

    I need some help with my suburban. It runs like crap cold, 37 degrees outside temp, missing and popping through the intake, does not seem to idle high enough, dead spot in throttle.

    It throws code #300, and #171 and #174,, but when she warms up, she purrs like a woman after you give a fat diamond ring.

    Any idea fellows?

    Any assistance would be greatly appreicated.

    Thank you very much.
  2. Z71_guy

    Z71_guy Epic Member 5+ Years 1000 Posts

    sounds like a classic intake leak, when its cold start the truck and spray carb spray along the intake and listen for changes in RPM if so its an intake leaking.
    Get the felt pro gaskets set our shop has had the best luck with them
  3. japsmash2001

    japsmash2001 Member


    Question. What else could cause my problem?
    Additional air valve? Coolant temp sensor? What could cause the problem that won't throw a code? Beside the intake of course.

    I changed the wires, but not the plugs, could old plugs with a excessive gap unable to fire the rich mixture be the problem?

    Does the intake leak self seal as the engine warms up due to expansion? It idles like a rock when warm.

    I sprayed the carb spray this morning but didn't notice it run better. We can try propane or map gas tomorrow. If the problem is the intake gaskets, how many hours does the book give for the job? Is it diffucult?

    Thank you very much!
  4. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    I'd check the coolant temp sensor. Normally it causes a rich mixture condition, but it may be the culprit even though your codes indicate a lean condition. Have you tested for a vacuum leak?

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