the car will sit and ilde fine all day long once you put it under load it backfires by backfire I a loud pop out the exhaust . Its very random it might do it once in a minute or 5 times . Just about everything on the car is new . Everthing listed is new : Opti,ICM,coil,plugs,wires,fuel filter, . The fuel pressure stays around 35 may go up to 38 or 39 but falls no less than 35 psi. I was gonna change the fuel pump but not sure if its the problem . Not showing service engine light or any codes on the scanmaster. Im not sure what to do ive triple checked everthing . Someone told me could be a stuck valve and to double check the valves. Everyones imput is greatly apreciated

 

Please post only on one forum. Do not cross-post.