I have an 88 mustang lx 5.0 . the motor was just out of it and i put in some new berrings and rings i never put a car back to gether b4 so im learning. i have bbk headers. ford racing wires, motorcraft plugs ,new alternator(motorcraft), hew coil (autozone), new battery, new ford rotor and cap, many new parts. i start the car and it will run great for about 5 min. when i got to move it or when the car gets hot it starts backfireing and sputtering and acting up. i cant figure out the problem, i know the wires are getting hot because they are close to the headers so i got somne taylors that i have not installed yet. im not shure if this is an electrical problem fule spark or vacume problem i have no clue. if anyone could help that would be much apreciated . thank you .
mean green

 

your distributor might be 180 degrees off...pull the cap off and take off the hold down clamp and rotate the rotor 180 degrees. put the cap on and make sure your wires are right. and advance or retard the timing if necessary.

 

Either your running really rich and the engine isnt burning all the fuel and or you have a exhaust leak introducing fresh air to the unburned fuel in the exhaust causing combustion. I would check your header flanges and make sure they are tight.

 

Yes, I would also make sure your timing is correct. With those symptoms, I would say it is off.

 

i have a header leak,and i beleve the rest of my exaust is tight. im prity shure my timeing is right because it will run well for a few min. untill she get hot then it starts acting up.im guna throw a new cap rotor pluga wire and coil on it in a few days maby that will do the trick if not im stumped.

 

I had the same problem with my car but only my car would act up and jerk and sometimes shut off i can almost gurentee you that it has to do with the fuel pump module or fuel related