Got a mis.

[Clark]

Hello guys,
I'm new to this community but have been checking out turbobuick.com for some time now. I have an 87 GN with a mis that I can't figure out. I put a crate motor in it 7 months ago and it ran great until 2 months ago when it developed a mis under exceleration. Since then I have replaced the BAR sensor, MAP sensor, MAT sensor, ECM, Coil Pack, Ignition Module, and TPS. No more codes show up and it still has the miss. Last night I replaced the injectors and regulator and still missing. The digital tach is way off also, but i'm not convinced they are related. There are no obvious broken wires. What should I check next?
Clark

 

[bosted86]

ok, stop throwing parts at it, its gonna cost a fortune. check your spark plugs after it has been running, the one not firing will be coated in gas if its a spark problem. also chek the gaps of the plugs. check your plug wires, i had a miss and found one had melted on the header. also check injector pulse with a injector noid light or put a long screw driver to your ear and then on each injector while car is running. you should hear each injector ticking as it is fired. if you cant hear one ticking, double check it with a noid light and you found your problem. just because you put new injectors in it does mean they are firing, the harness could be the problem.