2002 F150, all stock, but 10MPG... what can it be?

Question

What should I check? EGR cleaned, K&N filter, clean... 5-20 oil, could that be it?

Answer 1

new spark plugs, plug wires, timing, tire pressure. Don't forget driving habit.

Answer 2

First off throw the k and n away. I don't have the time to tell the bad points they do. But it will hurt the mass air flow sensor and cause a mpg and perfomace problem. There is a trick to cleaning a mass air flow and should ONLY DONE be someone that actually knows how and not someone that says I think I can. Or you will be out $200 + dollars. Oil is fine, Egr that is stopped up will set a CHECK ENGINE LIGHT on. Change the air filter and clean the mass air sensor, change the fuel filter, check air pressure, and do a correct MPG test for city and hwy driving, the local dealer can show you tsbs on this.

Answer 3

Since you have a K&N filter i'd look at your mass air flow sensor. Sometimes the oil from the filter makes it's way onto the sensor causing a power loss which would result in less fuel milage. You didn't specify how many miles you have on the truck, but if quite a bit I'd check into a tune up and fuel filter change.

Answer 4

Water in the engine has to be from 190 to 210 degrees.
The colder the water, the richer the mixture.
The way you drive also has everything to do with fuel ecomony. MPG should be checked on highway trips to see exactly how much it gets. Checking it just riding around town will show low.

Answer 5

Just guessing what about the 02 sensors of the catalytic converter.

Answer 6

I personally would check the plugs but I would ask yourself was my gas mileage better before the K&N install or is it worse after the K&N install? that will have an effect on your fuel trims.