Any definitive catches on this? I just bought my 98 GTP and i took it to the mechanic for a safety inspection. He told me that the person i bought it from put in a straight pipe which had removed the CAT. This was of course causing the cat efficiency code and my SES light. He had also said that it was throwing the misfire code complete with the flashing SES. It only flashes when i really jump on it. The mechanic and my brother, an ex mechanic, says that since the rear O2 sensor is either out of the exhaust, or getting readings with no cat, it is trying to lean out my gas when i jump on the throttle. This leaning out of the gas is what is causing the misfire in the engine. I still plan on doing a tune up on the vehicle with new plugs and wires and testing to make sure the coils are good. When i get on it it sounds like there is a fluttering air sound coming from the engine...the car continues accelerating but has moments of much harder acceleration...like i said i just bought the car and have still yet to dive into the engine and check it all out. So far its the only vehicle between the wife and myself so i dont want to start tearing things apart if i can't run up to the auto parts store if i break something...Im new to this whole tuning building thing so any and all help is welcome. Thanks
