Ok heres is the problem..... when slowing down to around 15 mph and attempting to give it gas again, the car feels like the tranny is slipping and then kind of falls into gear. BUT I took the car to the shop(who completely rebuiltmy tranny less than 10k miles ago) and they dropped the pan and everything in the tranny was completely fine. So they just changed the filter and put new fluid in, but the car still feels like it is hesitating and slipping. So I was wondering if there is anything else that could cause the car to do this?
I know the car needs a tune up pretty bad, could this cause it? Any help or suggestions would be appreciated, thanks.

 

Tune it up 1st and see what happens.