| | | quote | | Originally posted by steve1173: My 88 Formula w/auto. For the first 3 minutes or so on a cold start it surges from 500rpm to 1500rpm. I have changed all the sensors, checked for vacuum leaks etc. After 3 minutes runs perfect. Any ideas please. |
|
If it has a 2.8 --look to see if anyone took out the factory stop idle screw cap--if so they have an adjustment proceedure to re-set it along with the iac,---I fooled with mine for months before finally swapping the T.B. out for one from my 87GT--it stopped the surging---I had 1500 to 500 to 1500 to 500 for the same time you have, then it ran perfect. Remember each time you change a sensor, you need to either take out the ecm fuse or disconnect battery for a few seconds, then drive it over 35-45mph , and it takes some time to re-learn all the values. That T.B change out got rid of the surging so many people have posted about, but you may want to also check (at night) your exhaust manifolds to see if they glow (Bright Red-Orange ) while car is setting still , bring the idle up to around 2000-2500rpms and see what happens. So I have a great non-surging ide now--but bright glowing manifolds--tried the search the archives , alot have posted about them, but no fixes posted to date. My guess is someone has taken out your factory cap and fooled with the idle stop screw. Or you have a bad IAC and the Throttle body around the IAC needs cleaned out. Hope this helps some... if you fix it, Please post results.........
