I have an 01 Ranger Edge 4x4 with the SOHC 4l v6 and have been getting pretty bad mileage, I think. Im only getting 100 miles for a bit over half a tank. I do mainly highway driving. What could be my issue? I have no lights on dash.

 

Welcome to the forum

Neighbor kid with a siphon hose made my MPG drop, never took a lot but did take enough, lol

O2 sensors wear out, recommended change time for front(upstream) O2s is 100k miles.
They will make engine run richer than it should as they get older
And no codes because they are the sensors that SET the codes
Rear O2 lasts 3 times as long

So if they haven't been changed then I would change them on spec, even if its not the issue now it will improve MPG regardless if they are over 100k now.

Pull out a spark plug or two and see if they show Rich running, darker brown/blackish color

Check fuel lines by fuel filter, could have a small leak you can't smell, also in engine bay.
Cycle key on and off a few times(3 or 4 times) to build up fuel pressure in the system then start to check fuel lines under truck and in engine bay

 

I will check on these thanks!

 

One can't count on accurate milage going by the gas gauge.
You need to check the miles every time you fill up.
Often a fuel gauge will drop fast from full, then slow up til empty.

 

Thanks for the tip Ron. I will be changing mine. My mileage sucks as well. I hope that helps my slight miss at idle since I have tried everything else.

 

If you are referring to O2 sensors, then it won't help a misfire at idle
O2 sensors are not used when engine is cold, or anytime at idle or WOT(wide open throttle)

Try a bottle of Seafoam in the gas tank, cleans off fuel injectors tips, dirty injector tips DO cause misfires at idle

 

Half a tank is half a tank, no? Im going off of how many gallons and miles I have traveled off of half a tank. When I filled up, the truck took almost 6 gallons for half a tank. I dont get this as the truck is supposed to have a 16.5 gallon tank, yes? Is that accurate? Unless it keeps a few gallons as reserve when the guage shows empty. Im still going to do a tune up as well as change o2 sensors. The o2 sensors on my truck are factory. They should provably be changed as it is.

 

Really? Well let's see.....if u drive 100miles and top off the tank and it takes 6 gallons then u are getting around 16.7 miles to gallon, which isn't all that bad with a 4.0 quit reading soo much into the fuel gauge🙄 They are not all that accurate........but u know what is? Calculating miles divided by gallons when u fuel.......

 

Regular cabs used 16.5 gallon tanks, extra-cab 19.5 gal

But they should NOT take that much even dry, because its a sealed tank when gas cap is on the pump should shut off when there is about a gallon of room left in the tank, this allows for temperature changes and expansion of fluids

NEVER EVER keep adding gas to any vehicle made after 1990, you will damage EVAP system and it will cost you $200 to $900 to repair.
SECOND "click off" of the pump is it, do not keep adding fuel.

And no, the gas gauge is not at all accurate over 1/4 tank, unless its a fluke, lol.
Never found any vehicle gas gauge that is accurate over 1/4 tank.
Under a 1/4 they tend to be right on