random stutter

[90xsi]

hey i recently did some head work, mls headgasket, and cams. this is where the problem starts. once in awhile as im thrashing my car the engine light and o2 heater light will come on and my car will jerk followed with a loud bang. and i let it idle after that for about 5 seconds and check engine light and o2 heater light will turn off and car will drive like normail. cars fully tuned and afr are spot on. i've been racking my brains out trying to figure out whats wrong and its starting to get to me. anyone got any suggestions or point me in the right direction please.
thanks in afvance

 

[bazeng]

What ecu?

 

[90xsi]

its a tuned stock ecu. ive tried the ecm link and it still does it, ive also tried stock ecu and it does it. its driving me absolutely insane. ive cleaned the maf. im gonna try swap mafs over and change my cas and see if it makes any difrrence. its just weird because its so random. sometimes the check engine light and o2 heater light comes on and the car doesnt jerk. but most the times its a miassive pop from the exhaust and jerks then both lights come on but car is still normal after a few seconds both lights turn off automatically.