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My 86 corvette runs rough at idle around 500-600 rpm. It stumbles and hiccups when accelerating from a stop as well. I replaced the iac and reset it by jumping the a and b on the aldl, turning the key to on, waiting 30 seconds, unplugging it, turning the key to off and removing the paperclip in the aldl, and reconnecting the iac. Took if for a drive to see if idle would improve and was told the iac adjusts itself after keeping the car at 35-40mph for a couple seconds but nothing improved.
I don't know what else to do. Check TPS? Or do I just need to adjust the idle screw?
Make sure the timing wire that you seperate for timing is plugged in. And speaking of that what is the timing set to?
Vacuum leaks ???
What is the vacuum at idle ??
What is the fuel pressure KOEO ??
Also, pull the fuel pressure regulator vac line off and smell for fuel.
Old fuel filter ?? Dirty air filter ??
Check the bellows between the MAF and throttle body for leaks / tears.
MAF sensor dirty ??
Plug wires good ??
Any codes ??
Last edited by Vets-Vet; Oct 12, 2024 at 01:15 PM.
Thanks for asking WVZR-1. 1st time I ever thought UH OH due to winds. At 2am my TV antenna was whipping back and fourth so bad I thought it would snap but never did. It was movie scene style sheets of rain and at the end we had snapped trees, some water managed to blow past the window seals, a little water in the basement, stuff not stowed inside is missing even behind the outside garage walls, other peoples stuff all over, an extra mail box from somewhere, a few missing shingles and the knowledge next time to just go somewhere else if it looks that bad and the path is that close. As for the Vette see pic. I checked with sCarter and he is OK but near him pretty bad, I have yet to hear from Solar88 in St. Pete.
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Last edited by Vets-Vet; Oct 12, 2024 at 01:13 PM.
Idle screw: From the factory, these are blocked, as in not able to adjust. If yours has been unblocked, I recommend adding a locknut to it, there is nothing to prevent that idle screw from moving around without the block. Check the FSM for procedure of setting the idle.
Not sure what the idle is for the '86, but my '87 is usually 600-700 when warm.
rough idle help please
