I filled the HHR up with E85 twice in a row. I could feel the extra 5 horses and 5 pound feet of torque. The check engine light came on a few times while I had E85 in it. I coudn't tell that the engine lost any power and the DIC did not communicate any messages. I switched back to E10 and it hasn't done it since (knock on wood). Could the engine not being accustomed to running E85 somehow cause it to run poorly on E85?

I drove to Arkansas last weekend. While driving on US 59/270 just east of the Oklahoma line, I put the cruise on 55 (the double nickel still rules on all 2 lane highways in Arkansas...grrrrr) just to see what kind of mileage I would get. The highway goes through a valley, but there are rises and falls and hills along the route. The mountains to each side are steep. I drove all the way from the state line to Mena with the cruise on 55 (or 45 where required by law) and got a whopping 36 MPG, if you believe the DIC. It was getting about 28 and 30 or so at 65, but 55 must be its sweet spot for MPG. My mom lives in Mena and the nearest speed limit higher than 55 is in Oklahoma, and she rarely goes to Oklahoma, and she spends a lot of time on Arkansas 2 lane roads. She told me about how good the mileage was and when I got it I thought "24 overall? Really?" but I live in a city and take the interstate to work so I have it out of its efficiency sweet spot most of the time. A steady 55 or 60 on a flat road might net you 40 with a tailwind.

 

Unless you post up what the CEL code number is, it would be hard to comment on the issue.

 

Running E85 in 1962 Galaxie 500 would cause the CEL, in fact, unleaded would cause problems.
Wow, IIRC, the factory MPG was about 16.

 

Yes Bugo, please get the codes and post them here , the whole code please, as an example P0420 or P0010