How's the air filter? It sounds almost unbelievable, but my air filter was god awful dirty and I was getting 12 mpg in warmer weather back in November and December and I got an aftermarket cone "cold" air filter and put that on and I saw 14.5-15 mpg city immediately. I'm not saying to go get an aftermarket filter like that if you don't have the money or want to but I would say it was worth the $40 for a filter that never has to be replaced and the paper ones from a parts store cost $10-$15. Other things to look at, are the tires inflated to proper pressure? That'll suffer big time on highway. Have you put more aggressive tread tires on by any chance, like all terrains instead of the usual all seasons? Another would be the intake cleaner fluid you put in your oil or fuel. This is the type of thing that's very debatable. Personally I used to get the injector/valve cleaner stuff and I would feel around .5 mpg when I bothered to pay attention to what mpg I was getting. I then went to Zmax and put it in my oil changes and the 2nd time using it I could feel my engine running a lot more smoothly and from then on I did not really pay attention to mpg because I felt how much better it was driving. Also I'm not sure if you would know this or not. But I'll just say it, if you live in the Midwest like I do the, you know that this winter has been a fairly brutal one especially in regards to the temp. That could be another issue too. Once the engine and transmission warm up a bit that'll help but with the temps being as low as they are fuel economy goes horribly down. Right now I'm getting 11-12.5 city. But I also have a 5.0 with 264k on the original engine. But remember when it was warmer typical winter weather I was getting 14+ city. Just some things to take into consideration. If you've got anyone in the automotive industry or does back yard work for your family I would consult them, I'm an automotive student and I've been keeping my Explorer running for longer than anyone would have expected. And what I posted are some things that I've looked into and have helped me. Hope it helps!
