What does the Ecu ignore at full throttle

[southkurtk]

my 1989 sundance with a 2.5 turbo 1 engine.. backfires in the intake at part throttle but at full throttle and idle it runs fine... and free reving it runs fine.. only under load it backfires.. only thing i can think of is o2 and coolent temp? any other ideas?

[shadow88]

Incorrect ignnition timing, Incorrect cam/crank timing. Spark plug gap too high, Weak ignition coil, cap, rotor, wires, vacuum leaks, faulty o2, crap gas?

Any codes?

[southkurtk]

no codes.. all of the above have been ruled out except faulty o2.. When i drove home from work today. i unplugged the o2 no issues at all.. so im assuming i found my issue.. Gonna swap it out tomarrow.