Thanks, dolluper. Actually when I had the Opti distributor replaced last summer, I got the vented cap, so that shouldn't be the problem. I'm convinced it's a defective cap or something to do with the electrical stuff with the injectors (I hope not), so we'll see what my mechanic says. I'll do the other suggestons you posed to see if that makes a difference. I really thank you for the "possibilities", I'm having a hard time with this awesome car!....Sean