JDWalton

plugs, injectors, bad COPs, dirty / defective MAF or O2 sensros.

plugs / injectors / cops = problems with the burn. No spark or too little / to much fuel

MAF or 02 trick the car into sending in too much or to little fuel. Do you have a wideband 02 you can hook up?

mighted1987

No but i could get one, the tricky part and why after market cams dont do it, that mke it harder to point where is the problem

moosestang

So what does your vacuum gauge show at idle with the stock motor? It should be over 20 inches after the idle settles down.

mighted1987

Ill check tommorow morning. The problem is this farting happen only when the car rested for 4-5 hours. So it hard to test , It realy only when temp gauge is at is lowest, for the fart when cruising Seems like it normal cuz i have no cats, went to the drag today with my friend his mustang 88' was farting like me when loosing on throttle or down shifting he got no cats, im gonna bring the car in 2 weeks to a guy that only do mustang. He told me he got the whole setup n laptop to check n test the fuel n injector, he think it might be related
To pcm or wire. Car ran 13,50 103 mph with spins n weak 2.40 60' on street tire full air, Funny tho. 5 lbs boost less stock engine running nearly same Time then with the forged cammed ported 10 lbs boost setup.