MPG change, where to start looking? Options

[914Bryan]

I know this isn't an exciting high performance question, but a question just the same.

I'm having an issue with the mileage my 74 2.0 DJet and am wondering where to start looking for the problem. I commute 60 miles each way to work (120 total). My driving is 98% freeway, non rush hours so a steady 75 mph, motor is turning 3200.

I could always count on 32mpg, day in, day out. Over the last two months, it has slipped to 28mpg. I burn a tank a week, so this has been about 8 tanks of gas that I have noticed this.

Engine is running fine, no change in performance.

Would a tardy valve adjustment cause this? I'm a little over 6k since my last one.

Any ideas?

[jonvo4591]

I was in an autotive training class last week and we were on the subject of alcohol content in fuel. Apparently they just passed a law that allows up to a 15% average alcohol content in fuel over the course of a month. Here's the catch: gas stations don't have to change the label to tell you. There have been reports of as much as 30% alcohol content according to my instructor, and there are people he's talked to that have seen a consistent 3 or 4 mpg decrease.

I don't know if what applies in MI applies in CA, but it's just a thought.

[JamesM]

I was in an autotive training class last week and we were on the subject of alcohol content in fuel. Apparently they just passed a law that allows up to a 15% average alcohol content in fuel over the course of a month. Here's the catch: gas stations don't have to change the label to tell you. There have been reports of as much as 30% alcohol content according to my instructor, and there are people he's talked to that have seen a consistent 3 or 4 mpg decrease.

I don't know if what applies in MI applies in CA, but it's just a thought.

(IMG:style_emoticons/default/agree.gif) Step 1 should be find an ethanol free station.

Though you will wind up paying for for it anyways, so in the end its (IMG:style_emoticons/default/sheeplove.gif) either way.