Update: Went ahead and took the 99 Sunfire to another shop. As before, they could not find anything wrong with it. Kept the the car for 3 days. He did not charge me any fee. But he did have an idea. My gas hand in the car does not work. Has'nt worked for a long time. He said that perhaps at times the car was low on gas. And that the pump may have issue with a low gas level. And or this may also be allowing some dirt in settell in in the tank. And this dirt may find it's way to the fuel injectors. He recomended to keep the tank almost full at all times and also to put some fuel injection cleaner in the tank when I got gas. So I,ve been making sure the tank level is high. And also I've been useing the high test gas, 93, instead of the 87. And I put some STP fuel injection cleaner in. I've run it about a 150 miles so far. And it has run fine. So maybe that's it. We'll see. Buy the way. On top of my engine it saids SFI. Does this mean Single Fuel Injection? My repair book saids all these cars come with MFI. So I was just wondering about that.