somebody please help

[Graydon5oh]

ok this is about to drive me crazy. The car wont get over 3900 rpm and it start studdering when it gets there. iv checked for vacume leaks on the upper and lower intake. I have even taken it off and re torked it with new gaskets, and checked it for leaks again. i have replaced the map sensor the tps sensior. the firing order and timing is correct. ohh and its a 86 and the motor came out of my 87 which it was running fine in when i took it out. also the 86 didnt have this problem with the old motor.

 

[HISSIN50]

Do you run a TFI ignition? I dont know snot about duraspark or whatever came before TFI, hence my asking.

I would start with code retrieval.

If you have a TFI set-up, it sounds kinda like a bad TFI, which can be bench tested. Coil is also possible. Could be fuel related too. Plat plugs can cause issues at 4K also.

Well, I am glad to see that I narrowed that down nicely. (that was a joke).

Good luck.

 

[Graydon5oh]

tfi is new i forgot to mention that and i plugs and wires are new the coil isnt that old but i guess i could try that, but keep things coming

 

[Graydon5oh]

anybody else got any ideas anything may help