I had the Throttle Body replaced about 6 months ago and the car still stalls after I drive it around a while and it gets warmed up. It starts fine but as soon as I put it in reverse it stalls. It takes a couple tries to keep it going. The car will drive when I am just driving down the road for no reason after occasionally. I took it to a mechanic that glanced under the hood and said it was something called a throttle body placement sensor and said it would be about $750. Is there anything else that it could be?