My Trans Am keeps stalling when I put the car in drive or reverse. When I start up my car starts up fine and runs well, when I put the car in drive or reverse the car stalls, the RPMs go up and down and then it stalls but it does not stall in park or neutral. I had my carb rebuilt, the problem stopped for a couple weeks and then the problem came back. Does this problem sound like a carb problem, if so what should I do. Also the guy that rebuilt my carb said I had a small vaccum leak might that be the problem? I need help bad, if I don't get the car up and running my parents are going to make me sell it.
Thanks

 

could be an ignition problem...wires ,plugs ,cap ,coil pick=up coil
check these...

 

Where is the vacuum leak? Why didn't the mech. fix it? Fix the vacuum leak. That can cause your problem(lean idle mixture). Richen up the idle mix a little if it still stalls after you fix the vacuum leak.