If you purchased your vehicle from LA after 5/14/04 you probably got some bad Shell gasoline. Shell had an isolated problem with high sulphur content from one of their refinerys and the contaminated fuel was delivered to stations all over LA on that date, especially around the New Orleans area. Thousands of vehicle's sending units were damaged, including my wife's 1999 tahoe and my brand new 2004 Silverado. Shell paid for the sending unit replacement and gave every customer a $20 gas gift card, no questions asked. I don't know if the campaign is still active but here is the website that was posted in the newspaper that gave a list of participating dealers making the free repairs (
www.interactclaims.com/shell/). You can also ask a Shell station attendant for the info.