Low mpg

[Jefe22]

I'm getting about 12-13 mpg on my 2001 grand am 2door any idea why??? And also when I start it up sometimes it feels like it miss fires for a little but no check engine light.....

 

[richardgriese]

Which engine?

First so we are on the same page; you are calculating mpgs by gas into a full tank and dividing by milage driven - also you are not idling forever or speeding horribly (driving habits have remained constant as have routes).

Ok after that, when was the last tune up? Have you changed the fuel filter or cleaned the throttle body?

 

[Jefe22]

I'm give it a full tune up and see if that helps thanks!

 

[heybahler]

feul pressure regulator valve

Probably should also check the fuel pressure, if the pressure regulator valve is stuck closed, the pressure will be higher than normal make it run rich.

heybahler