08 SuperCrew 4x4 5.4 flex fuel 37k miles...

Seems that the gas gauge is not working like it should. I filled up last month and while driving around a few days later I noticed that the gauge had not moved. Then I got into the truck turned it on and it showed 3/4 full. Once it was at 1/2 full and when I turned on the trunk the next day it showed 3/4 full. By the time I got to work 5 miles away it had gone back down to 1/2 full. I add gas every 3 days or so since I don't trust the gauge any more unless I fill it up. Any ideas?

I did a search on here and someone else had a corrosion problem but I have no idea where to start looking.

Thanks in advance...

 

i have no experience with the f150 gauge, but every other gas gauge i had that was faulty it was the sending unit that went bad. usually it is in the tank and expensive.

to save $ i would skip the repair and just hit the trip meter after each fillup and filled up every 200 miles to be safe.

 

X2 on a faulty sending unit and expensive. I believe you either have to drop the tank of lift off the bed to get to it.

 

Last one I messed with was on a 1990 F150 and it had a float mechanism on the fuel pump itself which was mounted from the topside of the tank, if they still use that style of system I can see where the float would stick or get stuck, which is what it sounds like is going on to me what with it going from 1/2 to 3/4 back to 1/2. I am probably wrong, but that's my 2 cents on the subject. If I ever have to remove the fuel pump on my truck, I guess I'll know for sure.

 

This has been mentioned before. Try a couple bottles of fuel injector cleaner. Mine has done it twice, each time it was some bad gas(stopped getting gas there) and the cleaner worked once that tank had been ran out.

 

Ok, what brand of fuel injector cleaner do you all think I should use?

 

I used the stp one, but any should work. I don't think ours has a float?, but there is a sensor in there that can be fouled up and that is what the cleaner cleans... Took a few tanks of good gas for the gauge to start working right again.

 

Save some $, ad a pint of acetone to a 1/4 take of fuel...that will clean it.

 

Well, i went over to Wally World during lunch and found some Techron. I did a search on here for the fuel level sending unit and read about the sulfur problem. It was $6.47 for a 10oz bottle but it had a $2 off coupon. I had to buy 2 since my truck has the 30 gallon tank and I filled up yesterday.

I'll let you all know how its goes...

 

Seems that the Techron did the trick. After a few fillups with Techron my gauge is back to normal.

Thanks for everyones help.