[rbnj]

Hi All, I am at my wits end so if anyone can help it would be greatly appreciated. I have a '93 DeVille which I bought last year with 62,000 miles on it. When I bought it I had everything replaced new spark plug wire's ,plugs sensor's, etc. 4.9 engine. Up until last week it ran great then it started to miss and backfire and hesitate. I had the car put on a computer and it show's that nothing is wrong. I had the fuel filter changed because that was clogged, had new plugs put in and a new air filter. First the computer said that the MAP sensor and the DPS sensor were bad they were replaced and the car is still doing the same thing. O2 sensor;s are a year old and dont show up as bad on the computer. Had the ignition checked thats ok , had the exhaust system checked and thats ok. Every mechanic tell's me a different story who says fouled up injector's, who says, plug wire's, oh by the way I had the cap and rotor checked and their ok as well. If I let the car sit over night and then start it up in the morning the engine misses and the car backfires then it seems to clear and the car idles and runs as if nothing is wrong, then all of a sudden it starts up again with the miss's and the backfire's. Im totally confued as to what this could be. So if anyone might have any idea of what I should do it would be greatly appreciated, thank's in advance , Russ