So I had the great idea to chop of my exhaust right before the muffler and it won't idle properly. And thank you for any help. Btw it is an s4 na

 

cutting the exhaust that far back should have nothing to do with idling of the engine

sure you didn't mess/cut something else in the process?

 

I made sure to be careful when I was cutting. Are there any pieces that are important back in that area

 

You mean cut before the rear cans, right? Not before the main cat (or possibly presilencer if the cat was removed), for example, around the middle of the car? Because nothing back of the axles should affect the idle, but if you cut in front of the cat, you might have found electrical or air/vacuum lines to damage. Although nothing comes to mind as likely there, either, other than the aux port actuator line that plumbs in the exhaust near the cat - and shouldn't affect idle.