1988 Cutlass Supreme Need Help

I have a 1988 Cutlass Supreme and i just replaced the Carburetor, shocks, battery, fuel pump, and starter so the other day i started it and when i put it in gear and touched the gas it died. So i started it back up and when i left it alone it ran fine but when i put it back in gear it cut off again. I checked the carburetor to make sure fuel was getting thru and it was so i'm stuck if anyone can help me please respond or send me a email. My email address is [email protected] I really need the help i'm stuck