Still getting terrible gas mileage

[92rangersport]

I posted on here awhile back about getting bad gas mileage, i recently did plugs, wires, distributor cap, rotor, air filter, cleaned battery terminals, i forgot about a fuel filter and pcv. what can be making it get that bad of gas milege, it needs u joints, and my muffler fell off yesterday but thats replaced plus i didnt think thatd affect gas mileage. but i filled up on friday and drove home from work about 20 miles, then another 10 to the salvage yard and its below half tank any ideas whats going on?

 

[Bubba Bob]

What is the exhaust like? Black at all? Smell too rich? I don't know what was suggested before, but that sounds like an O2 sensor problem. That is the only thing that Ive seen make a 3.0 get that bad of fuel milage.

 

[Ranger44]

It shouldn't get that bad of gas mileage. Even with a bum HO2S......

I'd check for fuel leaks myself. Like the gas tank, lines, fuel rail, etc.

Are you sure you're actually using that fuel? Or is the gauge a little wacky?

 

[Bob Ayers]

Is it running bad? Has it thrown a CEL? If it is running ok, and no CEL, check your fuel gauge/sending unit.

 

[austinrick]

You're relying on the fuel gauge? What does the odometer tell you, i.e., mpg?

 

[92rangersport]

trucks running great, no fuel leaks or hints of gas smell, i went by cost of filling my tank up and odom. its got me lost, theres no smoke smells fine, doesnt smell rich like my mustang does....sucks because i would be getting better gas mileage with my 347 but being its winter i cant drive it. no check engine lights nothing to hint any problems but the bad u joints

 

[rickster]

Whats your water temp look like? Is it heating up OK? Processor will generally run a cold engine fuel enrichment until it warms up. If your not heating up fully because you T-stat is stuck open or your temp sensor is unhooked/bad your processor could be reading a constant cold engine.

 

[betomonroy]

If you are not burning it you most likely are throuing it away.
So check your fuel pressure to make sure your fuel pressure regulator is working properly.
If it is ok check for leaks in the system . Check the tank's filler neck and hoses...
All of them.

 

[Ger42]

someone syphoning your gas?

 

[betomonroy]

That too...

 

[thegoat4]

Bad U-joints and other drivetrain issues can burn a hell of a lot of gas.

Fix the u-joints, check tire pressure, wheel bearings, brakes, alignment, trans and diff oil, suspension bushings, and anything else that moves on the bottom side.

When I got my truck it had bad ball joints, crap tires, and lose wheel bearings. Fixing those gained me four to five MPG altogether. Flushing the gunk out of the cooling system and washing off the radiator core also showed an improvement. About two or three MPG IIRC.

Got a roll bar with big silly lights on it? Take it off and see what happens to your mileage.