My gas milage fluctuates from 24mpg to 29mpg traveling the same trip (280 miles). It is a carbed (weber) 1.8 86 wagon. I don't drive like a mad man, that is impossible with this subaru. I pretty much drive the speed limits. It has a hard enough time topping 75mph unless it is pointed down hill.

 

Any thoughts?

Maybe a small vac leak/intermittent? Do you have a vaccum gauge, what kind of shape is the pcv system in?

possible its differences in temp/air density that does it. I know that with my RX its happened. One time I got 29 going to Atlanta from Charlotte. Same trip later in the month...25.

I was leaning towards a vac leak. When I press the brake the engine runs different at idle. The PCV system is clear but not stock. I plan on pulling all my suspension and drive train out and putting it in another Subaru in January. Then I will check for leaks.

 

 

Anything else?