How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike S. Your Own Question
Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 6702
Experience:  ASE Certified Master Technician
Type Your Chevy Question Here...
Mike S. is online now
A new question is answered every 9 seconds

87 1/2 5.7L tbi constant hunting idle

Customer Question

87 1/2 5.7L tbi constant hunting idle
Submitted: 7 months ago.
Category: Chevy
Expert:  Mike S. replied 7 months ago.

Check if the throttle body is actually loose or the base gasket is bad. Grab the throttle body while the engine is idling and try to move it as hard as you can in a 4 directions. If the idle changes, check the bolts for being loose and if the bolts are good, replace the base gasket.

If this isn't the case, try searching for a vacuum leak. Be careful if using starting fluid, don't spray it anywhere near the exhaust manifold.

If neither of these work, perhaps there is some dirt in the idle circuit. Let me see if that has an idle air control or anything like that that can be removed and cleaned or replaced. BRB.

Expert:  Mike S. replied 7 months ago.

Do you know if the "idle stop screw plug" has ever been removed?

Expert:  Mike S. replied 7 months ago.

Remove the idle air control valve and clean out the passage in the throttle body using some carb cleaner or compressed air. Here are some instructions for putting that valve back on, make sure the distance that the valve extends (from the motor housing to the end of the cone); the distance should be no greater than 11/8 in. (28mm). If it extends too far, damage will

occur to the valve when it is installed.

Expert:  Mike S. replied 7 months ago.

If that don't' work, try removing that idle stop screw plug and adjusting the idle per these instructions,

Related Chevy Questions