My 94 Z28 is acting up. It surges at low rpm and bucks a bit under load below 2000 rpm in all gears. The idle is a bit choppy also but It runs out fine though with decent top end power. I don't think its the opti so maybe MAF or O2? I tried unplugging the MAF to isolate it but the car shuts down when I do this. Any help would be appreciated.