check ur iac, tps, and fast idle. u can also try n play with the idle screw on the tb. check for vaccuum leaks too. those are the most common causes of funky idle. my car does the same thing in reverse. its fine. just means that ur axels are going to be needing replacing soon, but u can still run em till they start to make clicking noises when u turn. i used to have an ls swap in my del sol (it is now ls vtec) and ran into the same problems.