I have an r33 skyline 1994, it has a bad case of backfire, it has very poor acceleration and when i accelerate it gets stuck at 3 rpm backfiring really bad, i have check spark plugs, fuel filter, coils, afm, vacuum leaks, i have cleaned throttle body, afm, aac valve ive had a mechanic check it he cldnt find problem, its undrivable and check engine lights on, timing strts up at 20 on strt up and slowly decreases to 15 as car warms up. Mods are
Splitfire coils.
550cc fuel pump.
3 inch turbo bAck exhaust
High flow turbo
Apexi pod filter
Apexi fc commander
Boost Gauge
Front intercooler
Boost controller
Lowered 1.5 inchs
Short shift gear box
What di you guys think