I truely feel like my car is broke. 1st I had to get a new alternator, I get the sulfer smell once in a while and the gas mileage is an issue too.

98CoupeV6, I have done what you recommend. I believe the tank holds 17 gallons. When I I fill it, I put in about 15 gallons.
I get less then 200 before I put in another 15 gallons. So 200mi / 15gal = 13mpg. For the 2800 miles I have had my car, this is the normal occurance. I uses 87 regular octane gas from Texaco. If I could get 21mpg I would be happy. Any suggestions? I do intend on taking it to the dealer.