AP Maps seem to run lean, did you get a check engine light? how hard were you driving your car? under or over 5000rpm? because it could have been that you were getting knock with the already lean map and then possibly a bad batch of gas.... did you just fill up your gas at a new station or with a different grade then what your map was designed? is this the 91 or 93 map? I can answer you further once I know these things. but basically you could have had a knock issue witch would cause a knock issue, it may or may not have messed up your engine depending on how long and how bad the condition was, reflash to stock and claim warrenty work?!?! worst case AFAIK bent valves is caused buy knock.