dyersford

I have been noticing a steady decline in my fuel mileage for no apparent reason what so ever. A few months ago I got a MAC air intake and an SCT programmer, the truck was doing great, I was getting around 17 MPG just normal driving habits.... Back and forth to work that kinda stuff. the last few fill ups I have been getting 12 MPG, I haven't changed the way I drive the distance or anything. I have tried to use additives to help get it back to 17MPG but nothing seems to be working.......... Any tips you hay have would be much appreciated.

torkum

Try cleaning the MAF with with a approved cleaner. It could be getting oil from the new air filter.

rplatt56

Have you been gassing up at your regular station? Alot of suppliers are now adding 10% Ethanol to the fuel to basically get rid of the ethanol. This will decrease your mpg. You could have carbon build up in your engine too. I have one station in my area of NE Florida that does not allow ethanol to be added to their fuel. My mpg in mixed driving is pretty steady at 17.7. I see you live in Florida, check out the Kangaroo convience stores and see if they have the " Ethanol" tag on the pumps.

dyersford

I always try to fill up at a Wal Mart gas station because I was told that they have the best Fuel around my area. Also the filter I have is a dry filter not like a K&N that you oil or anything......
What would be an approved cleaner for my MAF sensor???

torkum

This is the only kind I use:

SouthrnmudslngR

BTW I wouldn't use additives there are very few that actually work and they only help temporarily. What size motor do you have and tires? Just curious. Cause I get 12mpg in the my truck but I have the 5.4 with 33 inch tires. I know before I even got the tires though I had experienced a drop in my mpg's also. Never figured out why.

dyersford

I have the 4.6 with 33's also but the part the boggles my mind is the fact that I was getting 17MPG for quit some time then all the sudden it just dropped. Like I said I didn't change anything it just went down........ Thanks for all the help thus far, I got some of that MAF cleaner yesterday.

Mr B

Had the same problem and I know this sounds crazy, but I changed my gas filler cap. Got the idea from my wife's Toyota where if you do not tighten the cap enough the check engine light goes on. Checked my 97 and sure enough the rubber gasket that seals the filler from evaporating fumes was torn. Replaced it with a new Stant locking cap (these days not a bad idea anyhow) anf the MPG went back up. I had already tried to clean the MAF and ran Sea Foam through it and that did not help.

SouthrnmudslngR

Yeah I've checked my gas cap and it's good to go. But I'm thinking also the O2 sensor. I know the light normally comes on but my truck is 8 years old and the O2 sensors aint never been replaced. You've done a tune up on it recently right? Like plugs, fuel filter, air filter and well thats all I can think of right now. That is really low (12mpg) for being that it is the 4.6 and I have the 5.4 and we both have the same size tires and yours is single cab right?

dyersford

Yeah I just changed my oil like 3 months ago, I used Mobile 1 full synthetic.I also changed my fuel filter not too long ago and my spark plugs about 8 months ago, I checked my air filter yesterday and it still good I beet on it and no dirt came out. Ill take a look at my gas cap and probably replace the thing..........
Thanks again for all the suggestions they are greatly appreciated!!!