ok i got a 91 with 305 tpi it was running great then one day it started running like crap it would fall on its face when i stepped down on it, as per suggested by fellow members i went throught the fuel filter, straped the fuel psi gauge to the windshield while driving, that all checked out ok 42 to 50 psi, i checked my timing, and looked at the plug wires they are fairly new and i didnt see any bad spots on them the only other suggestion left is to replace the coil, wich i will be doing tommrrow my ? is can anyone think of anything else that might need to be looked at, it isnt throwing any codes so is it time to get out the checkbook and start throwing parts at it maybe a coil tps and some plug wires

 

How about the module inside the distributor.

 

My 90 iroc 350 was doing that. It would not rev past 3000. Also missing some at all engine speeds. What fixed mine was new fuel injectors. I checked the resistance and three of mine between 8 and 10 ohms. There other were 16 ohms. Might be something to check out.