Car was running ok after the rebuild, but was having problems with the SES light coming on all the time. This past weekend I replaced the TPS, cleaned the TB, and adjusted the idle screw. I also replaced both O2 sensors with AC Delco ones. Finally I tightened up the exhaust and capped the Borla so the exhaust wouldn't be so loud. Everything was ok, but on the way home the EGR (P0400) popped up. Didn't think about it too much, but the car then had problems idling and cruising, so I just got a new one. My problem with cruising and part throttle acceleration is gone and the car idles in the parking lot fine, but when I'm driving and come to a stop light or stop sign the car dips down to like 500 rpm and wants to die. Does anyone have a idea what is going on? I'm thinking vacuum line or something along those lines, but wondering why it has just now become a problem after about 200 miles of driving. Any input is appreciated.

Thanks,
Anthony

 

I got to thinking and I remember when my car had problems idling when I first started it up after the rebuild. After a day or two of driving it was fine...it had "learned". On Saturday I didn't have my scan tool handy so to clear the codes I disconnected the battery and touched the terminals together to clear everything out including the SES light. Could it be that my computer just needs to "learn" how to idle again?

Thanks,
Anthony

 

The P0400 code sets when the EGR valve is supposed to be open, and the PCM closes the valve briefly, and looks for a change in MAP. If it isn't seeing the required change, it may be because the EGR is stuck open. That would account for a stumble at idle. Have you checked it?

 

Yes, I checked the EGR and replaced it. The SES light went out, but I still have problems idleing when I'm driving. Sitting the parking lot it's fine, but when I get to moving is when it becomes a problem. Any ideas....I think it is because I reset the computer and it just needs to learn again. Is that wishful thinking or is there really something wrong that I need to address?

Thanks,
Anthony

 

The computer "learns" in a matter of minutes, and all it can learn is the long term fuel corrections and the IAC position for the correct idle speed. Once you are "moving", things like vehicle speed and throttle position come into play.

What is the "problem" you have once it gets moving? Surging? That would be a problem with the tune, or poor engine vacuum.

 

When the car is moving I don't really have any problems, it's when I'm coming to a stop with the clutch in that the car wants to die. A good example would be finding a space in a parking lot. If I push in the clutch and try to back into a parking space or turn a corner to the next isle, the car will try to die. Once I've stopped, the car will idle normally. I never thought about the VSS playing a role in this. The DTC did come up twice, but that was like 3 weeks ago and it hasn't come back since. I'm going to do a search on VSS and see what comes up.

Thanks,
Anthony

 

Couldn't find much on the VSS search I did, but I took a can of TB cleaner and sprayed along the intake bolts. I got some bubbling at some and on others I got small bubbles like it was boiling off the manifold. The whole time the car didn't idle up at all tho, just remained constant. I'm gonna hook up AutoTap and see what the vaccuum is. Bar.-MAP=Vac...right? I also have a vaccuum guage that I'm gonna attach to the manifold as well to see if the two numbers correspond as well. I do have a question about the manifold gasket. My brother put it on for me while I was at work and he said he didn't use any silicone, just the gasket....is that right? I always use silicone on gaskets just as cheap insurance, but if I'm not supposed to I won't. I'm pretty sure I will have to take the manifold off and put it back on so I want to be sure so I don't have to do it again. Thanks!!


Anthony