check you plug wires again look for burnt marks,even inside the plug boot. check your cap and rotor.did you make sure #2 sparkplug was tight, if thats all good,when you put it back together did you make sure that you put the lower intake gasket on right. it's easy to put it on backwards, i've done it and it will make it run like crap. the problem your having sounds like a vacum leak. do you hear a hissing noise like it's sucking air when the motor idles