Ok Today I reflashed my car. I recently put a Catback on the car. I was already running a Helix catted down and STI up. Switched from the 91 Cal map to the regular 91 map. I was taking it for a spin to do the kc value cheat. You know put it in third and at about 15 mph and punch it to the floor. Okay on my way back I was getting on the freeway Wasn't paying attention and bunced of the rev. limiter. When I got back home my car Was making a knocking sound not to loud though. I thought it was my exhaust rattling against some thing. I pushed it further over on the hangers. Took it for a test. 1/2 a mile up the road the noise got louder and it was not my exhaust. Its a horrible knocking noise. Car sounds like a F'ing truck . Any I idea what it could be. The car will start. But when you move it and let off the gas it im. dies out. It will start up again but rev it and it dies when it comes back down. Anybody have a clue it what it is?
Sorry so long but I am trying to be descriptive, again the noise is a loud knocking sound. also I am not throwing any codes.