Did you check the Engine temperature sensor?

Do another test for vacuum leaks as well.

 

Well, I tried spraying cleaner all around the intake system. Didn't detect any change in the idle at all.

What is the part in the system that operates to make the idle higher when the car is started and cold? I figured it was the IAC valve, so I replaced that, but it didn't fix the problem. If I could just identity the right part, I'd replace it! I hate to throw money at this thing just making guesses.

 

How do I check the engine temp sensor? The temp gauge on the dash seems to work normally.

 

There could be a second sending unit that goes to the dash only, but not the the computer.
The Haynes manual has a graph that shows how the resistance of the ECT sensor depends on the temperature. It also describes how to perform the test. Buy the manual or check with your library.

 

what happened man??? did you fix this issue??? You were on a roll and just fell off.....

 

Well, I'm still working on it. Here's what I've done so far:

1. Cleaned the EGR passages both upstream and downstream of the EGR value as best I could without taking the manifold assembly out. Sprayed a lot of carb cleaner into the holes, then blasted it through using compressed air. Got a lot of black gunk to come out.
2. Cleaned the MAF sensor (with MAF sensor cleaner).
3. Replaced the IAC valve (with used, good condition).
4. Replaced the EGR valve (with brand new part).
5. Sprayed carb cleaner all around the intake manifold area. No change in idle detected - I don't there's a vacuum leak.

So, the car does start and cold-idle better than it did, but it's still not nice and smooth as it should be. So, I'm going to throw a few more parts at it and see what happens before I give up on it. I have these on order:

1. Upstream O2 sensor.
2. Engine temperature sensor.

I'll report back once I have these installed.

Is this starting test my patience?? No doubt about it!

 

ok, we will be here

 

New O2 sensor is in - no change.

I'm starting to think maybe it's the fuel system - an injector partially clogged maybe? The car runs better once it warms up, but even then it's a little rough - something in there just not right.

 

Im not saying it will do anything, but have you tried cleaning or replacing the fuel pressure regulator??? Or checking the proper adjustment of the idle set screw???

 

No not yet. I have a copy of the service manual.. I'll take a look at those items next. Also waiting on the new engine temp sensor to arrive.