lgmoreland wrote:
One thought. The guy at the Ford dealership recommended I upgrade to premium fuel when I'm towing. I've run a few tanks and calculated I get about 15 (percent) better gas mileage without the trailer attached. When I tow on regular unleaded, my mileage drops from 19+ to 9 mpg. He said I should see a noticeable improvement when towing. Please no bashing, just a thought.
Sure give it a try.
Back in 1988 (crikey that sounds old now) I did a test between regular and premium with my 1988 F150 with 5 liter engine and manual transmission. Found out that as long as the price spread is no more then 20 cents between regular and premium, I actually saved money using premium due to the increase in fuel mileage. Not great, but there was an increase. Usually the price spread is over 20 cents, so I never ran it regularly.
When I have done a similar test with my 2008 F250 with 5.4l engine, I've found negligible difference in fuel economy. Hard to tell if there was an increase, or just smoother driving on my part since I was doing mileage testing.
Todays engines have pretty darn good electronic fuel controls, so they seem to make the most of whatever they are using. 15 percent increase is rather large - is that "hand calculated" (don't use vehicle's mpg readout) over a few tanks? With similar driving situations?
I have heard from mechanics, and this was awhile ago, that you shouldn't run premium all the time in an engine not "designed" for it. Something about carbon buildup on the pistons or something like that?
Edit: odd thing, I had to change the percent figure in the quote to a word in order to post this response.