I have an automatic 1997 Mazda 626 that has what I am guessing is an idle problem?

I have an automatic 1997 Mazda 626. First, let me start by describing the car because it has recently gained a lot of character. about two weeks ago i decided to finally get my CV joints repaired (which turned out was easier just to do a new axle, fine just do it). About a week and a half ago i hit a deer, destroying the hood, radiator, air filter, and both front fans, so its back to the shop. to emerge today with a brand new hood (and grill which has been missing since my slow speed front end collision back in the 90s). The only problem is the hood is green, which would be cool except my car is white, nice. The way i see it all of her problems have been fixed! Except this one nagging, and i mean nagging problem…it has what I am guessing is an idle problem?

When the car is in drive, but stopped it vibrates excessively, as if it is idling just a little too low to be clean. this goes away after i put the car into park or neutral, the car stops the vibration. any guesses?