Quote Originally Posted by wilder9032 View Post
my 06 grand prix is only getting average on the computer 17.7mpg is that normal? what could I do to get it better just cleaned the mas. it is the 3.8 liter base model
When my '06 hit 70k, I was getting similar mileage. I cleaned the MAF, throttlebody, and replaced the sparkplugs. It now gets 26-28mpg. Always reset your average when you fill your tank so you can monitor it properly.