hesitation and backfire when i punch it around 5,000!

[240 sr in s.a.]

i have a 240sx with a sr20 red top i shorted the ecu once and replaced it and ever since then when i punch it around 5 grand it hesitates or backfires...it happens on every gear...i changed the plugs (bkr7e's) and adjusted the cas, but it still hesitates it hardly backfires now....ant other suggestions or advice id really apprieciate it.

[Emperor_Tha]

Usually at 5k is spark plug gapping problem.

[240 sr in s.a.]

cant be they were at .032 and i just put the ngk's in at the same gap. i just put in a stage 2 excedy clutch and a fidenza flywheel