Hello all, first post from the newest member and proud new owner of an almost pristene 1996 C36 with 88K miles. I bought this car a month ago from a guy that could not make it run right. No power, CE light was on, hard starting and so on. He had the car listed at 13.5k and I talked him down to 6k...not a bad deal I think!

I replaced the MAF and all the power is back and it runs awesome everywhere but idle. I have checked the usual suspects, EGR valve, EGR tube at intake, O2 sensors, and a few others.

I searched and searched and found some great info on this site, but nothing to solve this issue. The 2 problems are exactly this: In the morning after the car sits, it starts right up and idles perfect. 5 mins later, the car stumbles at idle real bad. The other (and I suspect it is related to the first) is when the car is shut off and restarted within 20-30 mins, it starts right up... if I leave it for any longer than 20-30 mins, it cranks for 5-8 secs before it starts, but always starts.

During my troubleshooting, I measured vacuum at the egr valve and found that 5-8 in of vacuum holding the egr open half way. And that is exactly what is causing the rough idle. I tested the solenoids that control vacuum to the Secondary Air system and the EGR system and they open and close while bench testing.

SOOOOO, Finally, My question is, what sends a signal to these electrical solenoids that control air to the EGR? Like I said, when the car is warming up, there is no vacuum present to hold the EGR open, hence the good idle. However, the second I snap the throttle, 5-8 in of vacuum is present and messes up my idle. This is also accompanied by a P0400 and a P0411 CE light.

With all the knowledge that I have seen on this board, I hope someone can help out the newest member! Thanks so much in advance!! I am a former Ford and Acura mechanic and hope to share my experience with this car and contribute to this forum as it comes!

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