MAC2GrEEnZ94

Had to have the car towed home about 2 months ago, haven't started it since. Well a friend of mine hooks his laptop today to check for codes but the battery was dead. All of the codes were erased so now I'm left in the dark:

When the car broke down it backfired (flames out the pipes) missed, and died, several times. Again the car would start but continued to die, i'd give it gas and it wouldnt go anywhere, the brakes also seized at the moment. Until the break-down the car would miss (jump rpms) after the first few minutes of driving after a cold start. That's all i can think of to describe my problems.

Only thing the scan showed was that the o2 sensors had different volt readings (always 0.5 apart), instead of showing the same readings, i don't know if that has anything to do w/ the problem, i need some help bad, i'm clueless on this problem.

Anybody have some suggestions, any help is appreciated?

Edit: Sorry i left out mods, just the basic bolt-ons, no internal work
(i.e. cold air, pulley, knock module, long tubes, y pipe, cat back, car has been dyno tuned )