my car now idles, kind of, it stays a float as in it doesn't stall but it idles from like 1200 to 1500 or 900 to 800 to 700 all over the place, any common causes of this? or any other advice on the topic

 

So you've had the UIM off? Almost certainly a vac leak caused by a vac line left off or something like that. It's easy to introduce vac leaks when removing and reinstalling the UIM. Stick a length of hose in one ear and use the other end to probe around listening for leaks. Or use something like carb cleaner to spray around and listen for a change in rpm.