My daughter has a 96 Pontiac Sunfire with 2.2l engine. Recently as the weather got cold it will not start if temp is below about 15 degrees. This problem has just surfaced in the last month or so. Today a mechanic looked at it. He got underneath and tapped o the gas tank then got in the thing and it started. He said fuel pump is bad. could this be correct or is he just fishin. He wants over $500 to change the fuel pump. It just don't sound like that is the problem. The car would start when the outsided temperature warmed up. Need help guys