Bad Gas Mileage
I have a 2004 f150 XLT 5.4 and I was getting 18mpg avg. about 2 years ago, and since then it has been heading downhill. Now I get around 12 mpg avg, huge drop and I'm not sure why?
Here is what I have done:
Transmission oil change
Tire air pressure check (right on)
Spark Plugs (nightmare)
I figured it was the spark plugs since I have 80,000 miles on it, but that didnt help at all.
Any ideas of what could cause this much of a drop? Anyone else having similar problems? Looking for suggestions on what I should do, I would like to be getting around the 16-18mpg again.
Something strange does happen once in a while driving and I try to accelerate, my truck will make a loud noise (like i have straight pipes) and my rpms and speed will not increase unless i either hammer it or i let off and hit the gas again? Any ideas what this is? Maybe this is causing my truck to lose mpgs? This did start about 2 years ago?