Need help!!

i NEED SOME HELP .I got a 93 caddy dev . I chaged the water pump ,when i was finished i took the car for a test drive .seems it lost a lil power and it turns off when i do a shrp u-turn ,im thinking that maybe it was the crank pully that moved when i was changing the Wpump (i was trying to take the crankpully off)mayby timing got messed up .any help is appreciated

Did you reset the ignition timing after you changed the water pump? Because just removing the pulley wouldn't affect the timing. I don't remember if the crank is keyed so that the pulley only goes on one way, do you? Did you remove any spark plug wires, or knock one loose when you were working on it?
The turning off in a turn problem, sounds like a fuel problem. Did you check the fuel pressure?