Southern Stang 722

Hey mf'ers, I did some searching and couldn't find what I was looking for so I'll ask and see what you guys think. The car has surging issues when driving with the a/c on. When it is off it runs smooth as can be. At first I thought it was because of my delete plates but after it ran smooth with the a/c off that ruled that out. Sometimes if I run the car without a/c for a little while then turn the a/c on it goes away but not always.
The throttle body is clean
I do know it's about time for plugs

All mods are listed in my sig....This surge is just really starting to get annoying and would like some insight on this problem. Thanks for your help folks.

Southern Stang 722

It now does it while the ac is off also. It had the p0340 which the alternator did have a bad diode. Had the guy replace the rectifier bridge, and a few other things that needed to be replaced while he was in there. So any ideas?

Blacksmoke

Check for an vacuum (air) leak from the air intake up to the throttle body.
Feel ALL around the area and make sure to check ALL around the area, meaning the back parts that face the ground.

If you have had a new tune installed lately it could be the tune as well.