My 1990 Lebaron (3.0 L V6 automatic) recently developed several fuel problems. About 2 months ago the car was working fine. Then I went to start it one afternoon and it was very difficult to start. I drove it to work and back (about 45 minutes highway/city driving) several days. The only other problem appeared to be that at mid to high speeds, it would sometimes buck slightly like there was a transmission problem. On the way to driving it to my mechanic, the problem got much worse and the engine got rough. It nearly stalled out a couple of times trying to accelerate from stop at traffic lights. The roughness was there in park & neutral as well as drive.
The mechanic replaced the fuel pressure regulator (cause of the problem) and changed the oxygen sensor and did an oil change. The car seemed to be ok again. I drove it for a few days, and the bucking problem at high speeds returned. The problem quickly got worse. Now the car is very difficult to start again, and it will completely stall out if I accelerate much at all. It usually idles very rough in park. I tried changing the oxygen sensor (to a good one that was pulled at
50k miles), spark plugs, and spark plug wires with no improvement or change in symptoms. I've also changed the following items within the last year: distributor cap & rotor, fuel pump (in-tank), fuel filter, air filter. Through this whole ordeal, the computer diagnostic code continues to show code 55 (all ok).Any ideas as to what's happening would be much appreciated.