Ok guys i just got a 1985 i-roc z28, it has a tpi 305.When i got the car the fuel pump was wired to a switch on the dash, well turns out the the ecu was not sending 12volts to the relay when the key was turned on. I got a new ecu and that solved the problem, i got the car runing but it did not idle well, i hooked up a snap on scanner to look at the data and all the sensors seem to work like they are supposed to. so i got some propane and shot some under the intake and the idle smoothed up and it ran good.
so i went and got a plentum set for the intake runners installed them and checked the egr valve to see if it was stuck open. I put a new egr gasket and put it back together and i have the same problem. i checked all the vacuum hoses again everything looks good. If someone could help me out that would be great

 

How's all your electric parts (spark plugs, wires, cap, rotor, coil, etc.)? How do know your hoses are all good? They may have a very small leak and that would do it.