Again like i said in another thread...your d4 light flashes b.c your TCU has detected a problem in the transmisson...all and all...thoes Gen trannys blow ass its fucked...even though you didnt do a damn thing to it...I bet you cant rev past 3 grand either and it starts back firing when you try to push it past 3K rpm?? i had the same problem...but i fucked with my ECU to to make my Check light come on as well as it flashing...so i replaced it painfully from ECU direct for like 450 Bucks