I recently finished up changing heads, injectors, maf, on my 91. My local tuner set me up with a "start" chip. Right now the car runs like crap, I know that some of this is tune related but one problem that is driving me nuts is, when I shut the car off, I can hear some hissing from near the fpr/fuel rail area. I took the rail off and inspected the injector o rings and I found one to have a cut on it. I replaced the offending part and put it back together and it still does it. It also backfires through the exhaust and is hard to start (I have to hold the throttle open). Any ideas where to look, I have one more night to work on it before I bring it in for my tune, and would like to have my crap together when I get there. Ill pull an all nighter if I have to. thanks