about 1800 miles on the motor car was running fine and the afr looked ok

 

Just BC the afr was ok doesn't mean there wasn't detonation.

Check the plugs and bearings for signs of detonation

 

oh ok what should i look for? and what would cause that a bad tune?

 

on the bearings, look for the back side of the top bearing to be black, this indicates extreme pressure from detonation. Basically the shock crushes the bearing little by little and allows it to move around in the rod. The movement causes them to turn black.

You can google for pics of what spark plugs with detonation look like.. or if you can get some good pics maybe we can tell. They will look like they have bits of aluminum sort of "sprayed" on, they will be fuzzy with aluminum on the ground electrode and porcelain.

 

ok thanks alot man il take it apart tomorrow morning and take some pics!! hope thats not the case=(