Just came across this great forum after trying to find out more about the problem I had this weekend with my '99 Bonneville. First day the problem started car was difficult to start, sounded like it was going to back fire and sputtered heavily. After being started car ran fine and then sat for a day. Tried restarting a day later and the car wouldn't start at all. Sounded like it was really trying to turn over but wouldn't. Checked all the spark plugs and battery both were fine. Also checked fuel rail and it was getting gas. Let car sit for another day and was able to get it started after really fighting it. As I was trying to turn the car over it sounded as it had two days before where it really wanted to turn over but wouldn't. I began giving it gas and it eventually started. The car ran rough as it warmed up and again sputtered as I let it idle and give it gas. After a couple of minutes the car ran fine. I have since replaced the fuel filter and the car seems to start better. The car has always been a slow to turn over so I'm not sure replacing the fuel filteris going to solve the issue(especially after reading many of the other posts). Any suggestions? Thanks in advance.

Do you have a service engine soon light?

Could be a fuel pressure regulator...

I do not have a service engine soon light.

Hmm. So it won't be easy, then.

I would start with a tune up, including plugs, wires, etc, if you haven't had one in a while. Still could be the fuel pressure regulator causing fuel to shoot back to the gas tank. A fuel pressure check may be in order.

You need a good diagnostic and scan, though.

Thanks, I'll get in this week and post the results of the diagnostic scan.