i tried the higher octane and the fuel injector cleaner and neither did anything, so if I adjust the valves before you do I will let you know if that did anything......I didnt mean to write you so much or seem so bothersome but its just that the preludes are the black sheep of the honda community. Meaning it is harder to find other people with the same problem you are having/solution since there are less. I aprreciate you responding to me, please keep in touch.....someone suggested to me that it could be a defective spark plug (I have 51K miles) and ive never done them, but I do not think so......