I just finished putting my car back together. I had done a S5 intake manifold swap on my 87, was not happy with the results and decided over the winter that I would put it back to stock S4 manifolds. I just finished that this morning, the car started up fine, idled perfectly around 1000 rpm. When the car got up to temp., it started to drop in idle, which is normal for the car to drop to around 800ish when warm, but it got to the point where it droped below 500, stumbled and choked on me. Could the problem be that I have the vacuum lines reversed on the EGR valve and the EGR is staying wide open causeing it to choke out when it is up to temp. The reason I ask this is because I had to take the EGR off for the S5 manifolds. I am tempted to take the rats nest completely out of the car and cap all un-needed lines and nipples. Thanks for any input.
CHRIS

 

Anyone??!