Need Suggestions!! 05 Ford f150 v8, 5.4L 3v (Gas Problems)
 

Alright, try to explain.

When I got my truck used 2 years ago it use to be great on gas considering, lets just say, half of tank use to last 2 weeks now it last 1 week. I don't know whats wrong. I drive 1 hour all together twice a week on the highway to get to work & the rest of the driving is done to go shopping, that's it.

Recently I discovered the air filter seal was completely torn so a lot of air was getting in, I just fixed it but I'm not sure if that would effect gas mileage, I've had a someone say it does, and it doesn't.

I take the truck in for oil changes when it's due every time. Hasn't had a tune up for a while but it shouldn't need one.

05 F150, 5.4L 3v / 210K (Pig on gas now) Need suggestions!
 

Bought my truck 2 years ago used (05 F150 5.4L 3v / 137K) now it has 210K. I get a oil change EVERYTIME it is due, take very good care of it.

PROBLEM: Chugging gas like a pig now, when I first bought the truck I could use to drive to about 1 hr over all to work (highway miles) and back home, another hr at the end of the day. 5 days a week.

I use to go through half a tank of gas in like 1 week and a half. Which I think is great considering the vehicle. NOW I drive same distance twice a week and I go through ALMOST half a tank of gas just making the run twice a week now, WTF is going on!

ONE problem I thought my be it, Air Filter Seal was ripped apart I found recently and replaced it today, but I'm not sure if that will effect gas mileage. I've been told it most likely is the problem and another said It can't be. PLEASE HELP

First thing to consider, climate. Is it cold out where you are? You may be running winter blend gasoline which burns faster. My avg MPG calculations are on avg 2.0mpg lower than summer time running winter blend.

Next thing, what maintenance has been performed. Spark plug change? Fuel filter? Air filter? Cleaned MAF sensor? Cleaned throttle body? How healthy is the transmission, pan drop and fresh screen? Run any Techron fuel system cleaner?

How many miles on the truck, and how many miles since the last spark plug change?

Have you done the math to determine the actual gas mileage?

Also, actual mpg numbers would be helpful instead of just "I used 1/2 a tank".

you could have an injector issue too. does it run rough? CEL's? anything preformance wise that has changed?

yeah sorry, I'm not 100% sure about that. Have to get it tested. I think when we got it, it was at 27mpg.

It doesn't run rough what so ever, you would think it's brand new.

Thanks for the list, i'll look into it all. It wouldn't be the winter, it started before that.

I was told the spark plugs were changed at 100k, it now has 210k but the truck doesn't run rough AT all. The MPG I believe was 27, now I'd imagine it's around 22-25.

YOU ARE COMPLAINING ABOUT 22-23??????????????????????????? IF I GET 16 IM HAPPY!!!!!!!!!!!!!!!!!!! but then again i dont think this is too accurate, no 5.4 ever gets 27 consistently lol

Lol, I was told by someone at ford that this truck is suppose to get around 26-27 MPG.

You think wrong. There isn't an F-150 out there that will likely hit 27mpg. The 5.4L in the 04-08 F-150 is normally a 14-15mpg city/ 17-19mpg hwy.

Next time you get fuel, fill up the tank all the way and note the mileage (or reset the trim odometer). Then when you go through that tank of fuel and fill up again, divide the trip odometer mileage by the total number of gallons used to fill up the second time.

Oh okay, yeah I was thinking the MPG was off too. I asked a while ago.

You're do for O2 sensors, cops, plugs, and I'd even say new injectors. Also the maintenance Darren said. I'm a believer in being ahead of things before failure. Also I'd change hoses, thermostat, and coolant.