Car has 90,000 miles, takes three to four times to start, cranks but doesn't turn over until a little help by taping the accererator. Once running, the car runs fine until I slow down or go into a slow turn then the car stalls, starts right back up. Only happened now and then, but it seems to be happing more and more. I've changed the fuel pump, fuel filter, air filter, pvc valve, plugs, wires and oil change. What else could it be. Nothing shows up on the computer either. Possible pressure senor.?