I have a 84 dodge diplomat with a slant 6. It has 44k miles on it. The engine surges at idle after it warms up and also has a miss. Plugs, wires, distributer cap and rotor are new, I replaced some vacuum lines and haven't noticed anymore vacuum leaks. I checked the egr valve and it looks fine. The carb, fuel filter and fuel pump are brand new. I checked for slack in the timing chain too. This car had sat for a long time, and I dont know what else to try. Any help or ideas is appreciated. Thanks in advance, Jay

 

A V8 transplant?

 

Make sure the fuel tank vents aren't plugged.Try driving it with the fuel cap loose to see if it makes a difference.The ignition module could be going bad and could cause your problem.