Walt, Most acceleration problems are related to the acceleration enrichment circuit. If this circuit is not functioning properly you fuel mixture is too lean when attempting to accelerate therefore you will experience the symptoms you are describing. Additionally an "out of tolerance" CO mix adjustment will also cause hesitation. Concerning your AC vacuum problem, this may be the source of your problem. First check all of the vacuum lines and insure that they are properly connected. If you have a factory installed AC mode switch it is probably leaking vacuum causing the problem you have described. The vacuum canister is located in the left rear pontoon body section: Parts Manual 2/4/0 #13. You will also find the vacuum routing on this page. "We're here to help you" DMC Help / De Lorean Services / <dmchelp@xxxx> Web Site: <www.deloreanservices.com> ----- Original Message ----- From: Walter To: dmcnews@xxxxxxxxxxx Sent: Sunday, August 13, 2000 2:29 AM Subject: Re: [DML] Main Fuel Relay Mark, I have the exact same problem with my D, and mine is also an automatic. When I started it today for the first time, it idles fine. But when I step on the gas, it hesitates and makes a very soft back-firing sound. With a little warm-up time and a little coaxing, it runs almost like it should. I describe the problem as having trouble 'breaking the idle threshold'. Once it's running faster than 1500 RPM, then it accelerates fine after that. Other symptoms I have: When I am sitting at a light, take my foot off the break and put it on the gas, the car will give the same hesitation. Basically, the car will barely crawl forward. When I switch the a/c off, it accelerates much better after that. Since I installed a 'John Hervey' edition 140amp alternator and a Fanzilla, the car accellerates much better now. But still all is not right. Another symptom that I have which may or may not be related: While I am accellerating, the center a/c vents on the dash close so that only the door vents work. When I am maintaining speed, then the vents come back on. I hear that it is normal for some loss of vacuum especially on automatics under heavy accelleration, but on my car this happens under ANY acceleration. I'm thinking maybe I have a bad vacuum tank and/or the vaccuum advance isn't working on the distributor. Are you having the same vacuum problems that I am? Also, does the Delorean even have a vaccuum canister? And if so, where is it and how can I check it? Thanks y'all Walt [Non-text portions of this message have been removed]