Quote: You know the 4 cylinders are firing somewhat at some level, as you mentioned driving on expressway.
Agreed! has to be doing something at higher RPM.
I have tried to adjust the carb but it seems to be at its sweet spot right now. I had big problems with it a while back (RapidRobert can attest to that) and completely rebuilt it and fixed some bent butterflies the previous owner had bent.
I have sprayed carb cleaner around the intake, carb, spark plugs and valve covers and the engien speed didnt change. That seems like no BIG vac leak. Only vac ports are on the carb- one for PCV, one for ported (Vac Advance) and one is full manifold vac. All are connected or plugged. I also swapped the vac advance to the full monifold vac at one point but it didnt help.
PCV valve SEEMS to be okay. Its not stuck, valve moves back and forth. Is there a way to test it or just replace?
I really dont want to just throw money at the problem, I want to figure out what is wrong.
I will try to test the valve springs this weekend.
