CADILLAC SEVILLE ENGINE POOR MILEAGE

All Of A Sudden My Car Smells Of Gas And Is Getting Horrible Mileage. I've Checked For Leaks And Found None. I Recently Had A Tune-up Done A...

1996 Cadillac Seville Sls Bought It In May 2007 With 84,000 Miles And It Ran Great. Last Month I Started To Notice That When I Start It...