bad idle

this problem started a week ago. the rpm on the car is jumpin and it seems like the car wants to stall but it wont. when i turn on the a/c on the car the problems seems to go away. i already changed the pcv valve, sparkplug wires, fuel filter, distributor cap and rotor, and the problem is still there. today i got a egr valve at a junk from a 96 model and i didnt see any difference when i put it in the car. has anyone had this problem before?

did you Try spraying Carb Cleaner around the intake manifold to check for leaks?

Get an O2 Sensor. That might be the problem.

no an O2 sensor is not going to give it a bad idle!! If he had a Bad O2 sensor he would have a code for it. I am assuming he doesn't have a check engine light. If he does he would know if it was an O2 , If he has a code Po304 Cyl#4 miss fire , then thats definitely a Intake gasket

i got my codes checked today at a advanced auto parts and the it says that is a random missfire.... does it have to be cylinder #4 to be the intake manifold gasket.... or can it be any cylinder missfire..... i think the code that i got was po300