My 2005 FEH was doing 33-34 MPG pretty steadily until 4 months ago. Now I am lucky on the same commute which is 50% up and down a mountain to get 28.5 MPG. Car runs normal, SOC is good. Can it really be due to poor brand of new tires (stiff sidewalls/ lots of corners) and 10% ethanol? Changed plugs and air filter recently.

 

If you went from the stock LRR tire to a heavier tire that would lower MPG. E10 is the most harmful to MPG in the '05 FEH and I've been preaching that for years here on GH. I'd say my '05 MPG dropped 15% when I use E10 and I'd say that's your biggest problem.

GaryG

 

That you Top?