Since I've owned my FD, I've never had a proper idle. When I bought the car, it had a leaking LIM gasket which caused a 2000 to 2500 rpm idle. I replaced the gasket along with all the vacuum hoses, and a few check valves.

Ok, so after I did that job, I tried to adjust my idle by the proper procedure. My problem is that my car seems to idle at either 700 rpm or at 1500 rpm. It is one or the other, and never in between. When I'm driving it and put the clutch in, the idle immediately drops to 1500, and then *sometimes* will gradually drop down to 700. When its at 1500 I'm getting about 16 to 18 in. vacuum, but when its at 700 I get around 10 to 12 in.

I've been driving like this for a long time, and I'm finally going to try and figure it out. I've tried adjusting my TPS (it's in spec), adjusting the throttle stop and air adjustment screws. Today I unplugged my IAC and the car would idle down to around 500 and wanted to stall, but my vacuum was still low.

I'm convinced that whatever is causing the low vacuum is also causing the idle problems. I've looked many times for disconnected vac lines, but I've never found any. I also have not taken off my UIM again to check, though.

I'm thinking about doing a compression test just to eliminate a bad apex or side seal, but I really doubt that is the problem, because the engine runs fine otherwise.

Another symptom is that sometimes when I start the car, I have to give it a little gas or else it will just run at about 200 rpm and then die.

The car is mostly stock, 91K with original motor/turbos.

Any ideas?

Paul

 

paul.....when yo ufind the idle problem, the fix for the vacuum will be found as well. my car was idling ~1600 rpm after my almost full non sequential conversion and the vacuum was 18-20in. i finally got it adjusted with the idle screw and the air bleed screw, and the vacuum is now reading ~14-16, minus the crap autometer guage that does not set to zero when the car is off.....

if you are not getting any codes, like an air thermo sensor, then you most likely have an intake air problem somewhere. i could be wrong. do you have a gasket on the TB intake air elbow. i did not have one. i just went through and replaced all of the gaskets and put some rtv sealent on the TB elbow at the TB seam....

louis

 

I'm not getting any codes. I also have the TB elbow gasket. I'll probably end up taking off my UIM and seeing if I can find something wrong in there.

 

Bump... any other suggestions?