My '00 Si seems to crank a little longer than normal when I have less than a 1/2 tank of gas. Anyone else have this problem? Anything to worry about? I normally dont have less than a 1/2 tank but sometimes shit happens.

My 92 DX never had this problem. BTW I use premium gas in it at all times and Iso-Heet on cold nights (which seems to help a lot). Car just turned 30k miles and is never ran to hard.