Engine Reving

pgt_racer · August 3, 2003

Hi. My dad has a 96 full size chevy truck with a 4.3L and 5speed. The problem he's been having is when ever you shift into the next gear, the engine won't rev down for a few seconds, then i revs down. He's taking it to the garage a few times and the say there is nothing they can do about it. My question is can this be fixed so it drops down in revs like it should? It is really bad in the winter time, can be reving for as long as 20 seconds before it drops down to idle. Has anyone else had this problem?

ps. it has done this ever since he owned it, its not a new problem.

thank you for your time.

02 Silverado Z71 · August 3, 2003

1..Make sure there is no binding in the mechanical linkage between the gas pedal and the trottle body. Should be clean and no binds/kinks

2..Make sure that the throttle return spring isn't stretched. If it is stretched, the throttle blade won't return to it's "seated" position

3..Make sure that the throttle blade itself has no carbon build-up on it. This would cause a high-idle condition. Get some carb cleaner and clean the throttle body and blade

4..Make sure the engine has NO vacuum leaks - this will also cause a high idle

Any of these can cause a high idle. From what you are describing, every time the accelerator pedal is released, the idle stays high until the idle-air-control motor pulls the idle down.. Oh yeah, take the idle-air-control out and clean all the carbon off the pintle. All of these things you can do with simple tools and some time.

Huntaholic · August 4, 2003

I bought a 96 Z71 5spd new in 96. It did it from day one. I took it in several times and they always told me it was normal, they designed it to do that, it was easier on the clutch etc... etc.. etc.... typical dealer bull$hit.

I kept it 2 years and traded it in on a 98 built with the exact same options. It did it from day one as well. I gave up years ago on getting it to idle down like it should between gears. It has 78K on it now and it is still doing it, no better, but no worse either. I KNOW it is a design flaw, an engine SHOULD NOT be set up to run like that, but they would never fix it and I never figured out how to do it myself. A computer reset DOES dramatically help it, but only temporarily. Good luck, if you figure out the problem be sure to post it so the rest of us can get rid of the high revs!

99-2door · August 4, 2003

Have either of you tried disconnecting the cruise control module to see if that makes a difference? Disconnect the cable from the engine, not just the electrical plug. I know you don't have your cruise turned on, but it could still cause this if there is a malfunction.

pgt_racer · August 4, 2003

Ah i see. Thanx for the replys. The dealer told my dad that also that it was "designed" to do that. No, it doesnt' have cruise. I guess we will try that stuff that 02 Silverado Z71 suggested.