Hey guys I've developed and issue in the past month or so. My car tends to backfire at around 6000rpms....I've checked fuel cut and launch control etc so it's not ecu related. Afrs on wot are good at 11.8-12.0, changed out and gapped spark plugs 3 times(8 heat range don't make it better) no egr on the car, fuel pressure goes up as it should...I'm stumped
I've also noticed in the low rpm range of 2-2800 on wot is sorta hesitates and stutters Abit and leans out to about 13.5-14afr....it's wack!
Mods are
2.4
Fp black
double pumper
id1300
Spoolinup cop and supporting mods
Please help lol

 

So I done a boost leak test and found a leak but made no difference ... Damn it

 

Back fire or after fire?
Back fire- up the intake
After fire- through the exhaust.

 

Through the exhaust mate

 

bump! well its been this long and i still cant figure out this problem....its turned into a random misfire through the exhaust. things ive checked.
boost leaks
injectors
coils
coil wires
sparkplugs + gaps
im at a loss about to give up
one thing tho, i have a sp exh cut out and when i force it shut on a wot pull it doesnt do it.....just strange

 

remove the COP and put the stock ignition back in and see how it does that way

 

Ok will do tomorow! But won't that make it worse? I've also put on other cop kits on and done the same but I will try it