Serious drop in MPG

I'm at 26.5K now. My 30K guide does not mention fuel flush. I have not heard good things about those injector cleaners.

 

.041. The old ones looked really good. 4 were gapped on spec. The other two were at .047 & .046.

 

Thanks for the info, Chris...been waitin' on an answer to come down the pike!

 

Full Throttle and a quality injector cleaner is as good as a stealership "flush" anyday. A dirty air filter is a more likely cause of bad mileage...Starving the engine for fuel is not going to result in more fuel being consumed. Mileage is more affected by the elevated viscosity of the oil in the diffs, trans, oil pan, and T-case.
A Fuel system issue will throw a code, cause hesitation, or stumbling.
And I believe denser air means the thottle is more closed, therefore causing more pumping losses.

 

And winter gas is merely more volatile, it has very similar energy content. Not enough of a difference to affect mileage.

 

Ethanol is present year round, whether it is 5.9% or 10% (unlikely), the energy content difference is negligable. Winter blend gas vaporises easier, to oversimplify the matter. Summer gas is the opposite to prevent vapor lock. Ambient temperature is the overriding factor.

 

I won't argue that temperature is the biggest factor. Cold enrichment, thickening of lubricants and extended warm up times all contribute.

I will disagree that energy content of ethanol and gasoline is negligible. According to the chart at http://en.wikipedia.org/wiki/Gasoline ethanol is about 2/3 the BTU content of gasoline on a volume basis. I frequently check mileage and find that I get better mileage when I travel to areas that don't use gasohol as is common in Illinois.

 

So the difference in energy content between a 3% difference in Ethanol qauntity is 3% X 66% = 2% energy difference. (If you can detect 2%, well....you can't.)
And I didn't state that Gasahol doesn't hurt mileage.
In areas that blend Ethanol, it is year round, usually between 6% and 9%. Like I said, minimal energy difference summer to winter. There is roughly 2-4% energy difference vs a non Ethanol added fuel, but that wasn't the topic being discussed. I believe winter mileage drop was being discussed, not fuel formulations based on what locality you are getting gas.