I HAVE searched through-out the NICO archives for my specific problem and though I have seen some others with similar issues, none like this. Heres the skinny:1990 S13 with 21K on .0020 over KA. The engine gave out due to blown HG that warped the head. I rebuilt the bottom-end with stock components and had the head decked. It came out just over min. thickness so I had to use a head shim with the HG. I know that the head work raised the comp. ratio but not sure by how much. Anywho, the shim lasted about 5K. I bought another head with fresh valvejob springs, etc., etc. and put ANOTHER HG and replaced the head. All seemed fine for awhile until about 3 months ago...when... starting from overnight sitting, or about 6 hours, it will idle up to about 800, then fall down to about 400, and slowly continue to fall until it quits. It responds to throttle input properly during this and drives fine, but just won't idle. BUT...when it is up to operating temp after about 10 min. of driving, idle falls to normal (750-800) and stays there, runnung just fine. Question: I have read that the IACV could be the cause of this. I believe this is the small black box on the driver's fender well with hoses going to filter box and exhaust manifold. I am sure that this is how the engine reciculates warm air into the intake when it is cold. I am, however, not sure what to look for in regards to a problem with this unit.
Has anyone had a cold-only idle problem and if so, how was it remedied? Also, units replaced during the rebuild and since (not because of the present problem) are injectors, fuel filter, ECU, plugs, wires, cap, rotor, most of the vacuum lines, radiator, water pump, alt, and a few, I'm sure, that I cannot remember right now.
Anyone who can shed some knowledge on this will be greatly appreciated. Sorry this is so long but if I want someone to help they should know as much info as possible.
Thanks again!!!!!:ylsuper
