Hello Everyone, I'm new to this forum but been around engines for quite some time. I'm not an expert but have already tried a couple things on this car and just want to get it to run good enough for the next guy/gal to enjoy.

Here's what I'm experiencing;

High Idle primarily at about 1500-1800rpm but will also jump up as high as 3k as I've been attempting to diagnose the problem. I haven't driven the car so there's been no learn time for the computer.

SES light flashes code 12 and continues to do so as long as I have the AB jumped. SES light will not go out while engine is running.

Plenty of noise coming from valve-train, almost like a solid lifter engine.

It also has a slight miss that I haven't attempted to diagnose but thought I'd adjust the rockers first and see.

Here's what I've researched and work I've performed;

1) Replaced the IAC and performed the install procedure to set initial idle. This was the only time I was able to get the car to idle below 1k but after I turned the key off and started it again, it jumped right back up to 1800 - 2k.
2) Checked TPS for voltage and that's good but can't seem to get a correct resistance reading.
3) Set to factory timing at 6* BTDC with EST disconnected
4) Replaced Cap/Rotor
5) Replaced PVC valve and checked brake booster for leakage, none found
6) Replaced O2 sensor
7) Sprayed carb cleaner all around intake and hoses, no leaks found
8) Has a crappy after market intake hose on it with a cone filter at the end. I plan to find an original or equivalent to replace it with. Seems the wires/hoses that went to the original air cleaner box have all been disconnected and plugged.

Any ideas and/or questions welcome. I'm sure this has been encountered here and I searched the boards and have used some of the info to diagnose this car but I'm kind of stumped and don't want to continue to throw money in the way of parts at it if I can help it.

Thanks, Jim

Sounds like a vac leak but post up a picture of the engine compartment if you can.

Here are a couple pics. Please excuse the disaster of an engine bay this thing has, the previous owner(s) were real hacks. I'll be correcting the air induction and restoring the engine bay to a presentable looking condition but would like to get the car to run properly first. Any suggestions on an aftermarket cleaner box would be great, otherwise I planned to source an original box system from a local pick-a-part yard unless someone here wants to part with either for a good deal.

If you see anything out of place in there, let me know as I'm not real familiar with this car. If you need close ups of anything I can also provide that as well.

Looks like someone also replaced the Alternator and EGR recently. I replaced the serpentine belt.

Thanks, Jim

Are the injectors from southbay or fic. Fic uses duel o rings to seal the injectors from vacuum leaks. Southbay has a glued/presses on fit pintle extension.

No idea what brand they are, they must have been changed by the previous owner. Can you tell by the pics I provided ? I sprayed all around the injectors with carb cleaner and no change in idle so I don't think they're leaking any air.

what are you using for coolant recovery tank? I see the hose going down the front by radiator.

Did the idle go down when you set the minimum idle speed ?
If so you could have a bad ecm commanding the iac out.

No recovery tank, car came to me on a trade like this. I need to source on of those as well so if anyone has any of the original parts I'm missing for a reasonable price, please let me know as I plan to visit a local pick-a-part when the weather dries up a bit and wouldn't mind not having to make the trip.

Yes, the only time I was able to adjust the idle down to 650rpm or so was when I followed the steps for setting up the IAC. To get it to idle at 650-700rpm (it jumps up/down and is not perfectly smooth, it has a miss and the valvetrain is clattering a bit), I had to almost screw in the idle set screw the complete depth. I plugged the IAC and EST back in while it was running at that low idle and nothing changed immediately. As I continued to allow it to run for a bit more at idle and as I brought the rpms up a couple times by rapping the throttle, it settled around 1000 and would not go back down to the 650. The engine was already warm when I performed the IAC setup procedure. Once I turned the car off and re-started, it shot back up to 1800-2000rpm.

I plan to perform this procedure once more and document exactly what happens as the first time was just familiarizing myself with the procedure and I didn't pay too much attention as I thought I fixed it. Any tests you recommend or what to pay close attention to while I perform this install procedure on the IAC again that you can suggest ? I don't want to just buy an ECM on the hopes it's the problem, just to find out it's not as others have. Any test I can perform to eliminate the ECM ? Or am I at the point of bringing it to a shop for another set of eyes and digital diagnosis ?

Thanks, Jim