ok i need some help here with a pretty bad miss that starts around 3500. and the check engine light doesn't come on until about 20-30 minutes of driving the car. it gives me a rich exhaust and a electronic timing control. the one that goes off when the bypass connector is disconnected. (i have made sure multiple times that it WAS connected) it will drive fine until i get to around 3500 rpm and then it just starts cutting out and doesn't want to rev much higher. for one i know one of the plugs that the ceramic is cracked. i am going to replace asap. its a rebuilt motor with about 500 miles on it right now. it has a new accel cap and rotor, distributor, taylor wires, msd 6al, msd blaster2 coil, new ac delco plugs except for the broke one. i just barely replaced the plugs but it was doing the same exact thing with the old plugs that were pretty fouled out but none of them were broken. so i know that i need to replace that one plug but would that fix it or is it related to something else. it has a .510 .520 lift cam with 230 236 duration. and flattop pistons and the heads were cleaned with a valve job and everything.

 

any help???

 

fix the plug ,youre lucky it doesnt skip all the time,jimmy

 

ha yea that what i thought thanks