Ok here is the rundown I have a 383 stroker, 9.5-1 compression, F.I. compatible cam, dart iron eagle heads, edlebrock tbi intake 670 tbi with a spaced stock injectorpod venom hp 88lbs injectors & vacuum ref.Fuel pressure reg stock distributor, performance module and MSD coil Long tube headers/dual flowmaster exhuast 02 sensor is in the collector and a custom burned chip Now Here is the problem. When i start it up cold it backfires thru the exhuast for the 1st 30 seconds to 1 min of running. after that it is fine. NO check engine light No codes With the scaner hooked up when it is acting up , all the sensors are working properly <temp sensor with in range alon withall the others. Fuel trim is good fuel pressure is good timing has been set from 0deg to 4 deg, Runs the best at 2 deg but does the backfire thing no matter what. It isnt running rick or lean and after that 1st miniate it runs like a F%^&ing Animal. HELP!!! im at my wits end, I even call the place that burned the chip and they never heard of anytihng like thisand couldnt steer my in any direction except to brin the truck to there shop in oregon i believe.. /forums/images/graemlins/screwy.giflong hual frion Jersey.