running rough

i have a 95 sts sometimes it runs rough and will stall at idlle. idlle speed will go up and down and when you step on the gas it leaps forward. i get a p036 problem code witch is egr valve pintle out of position and a p095 witch is stall condition detected but they are both marked as history. sometimes the service engine light is on sometimes off. can anyone give me some more insight into this problem. :uhoh:

Well, the codes right there say what the problem is! The EGR valve is probably getting gummed up with carbon. I had the same problem with a '94 Deville Concours I used to own. I removed the EGR valve, cleaned it up and the problem never returned. It's worth a try. And if that doesn't cure the problem, I'd suggest a new EGR valve.