[mustangrobert84]

i have a 89 mustang gt with a built 302 i have roucsh heads roller rockers and a mild cam it will only run on the non ho fireing order but it back fires realy bad when it is and it will only back fire on the ho fireing order please help

[need4spd90]

you need to check the distributor,make sure its not 180*(or even a couple teeth) off..when the piston in the #1cyl is at TDC on the compression stroke, the rotor needs to be pointing right to the #1 mark on the distributor cap. make sure your wires are routed correctly in the HO firing order. also check to make sure your timing is accurate(or at least close to where it should be)..base timing is 10*

also,did you properly degree the cam when you installed it?

[EagleAutosports]

Was the cam meant for the H.O. firing order? Or do you know what cam it is?

[StangLX93]

like Eagle said, is the cam an HO, or non HO, that is the only way you'll have a non-HO firing order all that is dictated by the cam, and the ECU will not fire anything else unless programed otherwise, double check your Dist. and TDC alignment, that is your problem, unless the timing chain gears have slipped

[mustangrobert84]

my car will not run a HO .. but it is an HO but the car wont run on that firing order... omg! when the car is idleing it has no bk fire when i put my foot on the gas but going down the road it does... =( help!

[need4spd90]

have you done what we've suggested so far?