starting issues with 89 buick

Sometimes when I start my 89 century (3.3) fuel injected. It cranks and cranks and cranks but doesn't turn over. I stop, and start cranking again and after about 3 seconds it starts to catch and finally starts...it sputters and putts and almost nearly dies unless I give it gas. Sometimes it does die if I do not give it gas. As it starts, sometimes I little puff of what appears to be white smoke out of the tailpipe and I can smell a bit of gas. I shift into drive and as I go, sometimes it hesitates. When I come to the first stop, it almost ALWAYS hesitates when I leave again. Never does it a second time. In the morning, I NEVER have the starting problem. I described this to a mechanic and he said that's a standard problem on GMs, and provided little more information. My 84 caddilac did the same thing. Any ideas? Thanks, Kevin

look for gas in the fuel pressure regulator hose, check fuel pressure also when this happens, very tough to diagnose on the net.