I get 9.5 mpg in the city and I have a V10.

 

my gas mileage used to suck now its goin up up up i used restore now im in the process of using different injector cleaners next im doing a tune up

 

sweet Vdub

 

Pull the air cleaner and open up the throttle body and look down the throat. You shouldn't see any oil pooling down in the intake. You can even take the TB off if you feel like it, as this makes the inspection easier. Use a small mirror and flashlight is you have to (to see into the corners).

Whack the cat with the palm of your hand (when it's cold) ... it shouldn't rattle. Not a 100% check but if it does rattle ... it's a problem.