ever refreshed the oxygen sensors? pre-cat would be my first one to change, mesures the air/unburnt fuel ratio. the second one is to confirm the cat is doing it's job correctly, check the connection wires first, could be something there.. or else , test for an air leak, gently spray some break cleaner around the intake hoses and manifold while the engine is running, engine will suck it up if theres a leak and will rev. good luck |