Mpg drop big
 

Hey guys I got a 90 f150 with 302 5 speed. I've had the truck for about 6 months now. I had been getting anywhere from 20-25 mpg in the truck but now it's dropped to 14 15 this past month and have filled up 6 times and checked mileage. I have replaced o2 sensor, air filter, oil and oil filter, coolant sensor, PVC valve, checked all vaccum lines I could and trans fluid and checked tire pressure and still can fix it. I drive 55 always and have not changed routes or habits. Any help would be great this is my main vehicle!!!!!

Got dual fuel tanks?

Did you stop smoking drugs? I'd have to be high as a kite to get 25mpg.

Not as far off as you might think. Had an 86 with the EFI 5.0 and an SROD that would consistently get over 20 mpg.

Dual tanks and the possibility of fuel transfer is a possibility, but I thought that was still the three pump setup?

LOL I was thinking the same thing

Winter gas maybe? Depending where you are that accounts for a solid 10-20% drop in milage.

LOL

that right there's funny, I don't care who ya are

Yes the OP's truck has the three pump setup that uses a dual function reservoir. That reservoir is also known to cause the fuel transfer issue.

Even then it would be difficult to get 25!! Maybe once I can see happening...:-X0A6

My '90 didn't.

I used to get 18-19 in the summer, but as soon as it drops below 34-40 14 is all she will muster. I think with the wear on it the mileage is going down more but not too worried yet

1989.....was the last year.

Oops

Lmao. Maybe he checked it going down a one mile hill in neutral

Thanks for all the replys!!!!! Just filled up again today I got 20 mpg this week, but it's been warmer this week maybe it was just the cold weather. I asked at my chevron and none of them new anything about there gas...... I use the 93 everytime. I'll try to see how it comes out this week