I have been battling this for about a month now...well ever since i purchased the car. I know there are threads about this and Ive read through all of them trying to find the root cause to my issue.

When driving the car and stopping at lights, stop signes, ect the car will quickly drop to around 200-300 rpm for about 3 seconds triggering the oil light to flash a little and idle very rough then the car picks itself up and it idles high for a second.

After reading threads, i have checked for boost leaks, REPLACED the IAC valve, cleaned the MAF sensor put new plugs and wires in and replaced the front 02 sensor and im still running into the issue. I did notice today the car has a very slight injector leak.

Any thoughts on what my next step should be? I really dont want to take the car to the dealer...

Car has intake, re circ valve, and the typical bolts ons


Thanks in advance

 

I forget the actual name of the part I'm referring to but I thinks its called an idle control valve/solenoid underneath the intake. That could be your culprit.

NOT the IAC....but it is underneath the intake manifold if I am not mistaken...someone else please correct me if I'm wrong....

Just something else to consider!

GL and post back if you find a resolution!

 

are you talking about this? http://www.extremepsi.com/store/prod...at=1060&page=1

 

Thats the IAC valve, I just replaced that and it did not help. Starting to think now it could be the BOV (it is recirculated)

 

No, not the IAC. Let me see if I can find the name of it.

 

I was thinking about the MAP sensor located on the passenger side of the intake manifold..on top...Sorry..not underneath the intake as previously stated.

I don't think it has anything to do with your idle...but I'm not sure.

GL finding out the issue!

 

ah thanks, anybody else have any ideas?

 

Have you done a boost leak test?

 

Any check engine lights??? I'd check to see if your maf sensor is dirty......or if your front 02 sensor is working properly, both have an affect on air fuel readings and if either are defective, then they'll cause survivability issues. Make sure your oil level is full, the flicker of the oil light could be caused by the car almost stalling out. Check those go from there, good luck.

 

no cel, cleaned the maf and replaced the 02 sensor. im going to do another boost leak test though

 

What intake do you have on the car? Hard metal intakes can cause this, even with tuning it never seems to go away. They resonate a frequency that the MAF does not like and cause thecsr to stutter. Same reason why MAF cars idle poorly when sitting next to a huge cammed v8 car.

This is why a lot of people have moved to the silicone-based intakes like the Perrin, it helps a lot. Otherwise, speed density conversion. Easy peasy.

 

Have you set your BISS screw properly using EvoScan?

 

My 03 would do that even with all the stock parts back on. It does have cams but not anything drastic.
The best "fix" I have found for this was to increase the timing in the idle parts of the map. This keeps my car idling pretty well all the time.

 

Thanks for the info guys, it does have the Fujita intake on it. I have not adjusted the BISS screw, from what ive read up on its never a good idea to mess with it (even though I looked at it and the black cap is missing) so im thinking the previous owner may had messed with it. I didnt know about the speed density kit...hmm

 

You should make sure your BISS is set up correctly, by using evoscan. It should/may help.