i am starting to notice a huge drop in my gas mileage. on average i could get 300 miles on one tank and now im gettin 200 miles. (92 ranger 2.3L 5spd) i recharged my air filter and that didnt help. i cant think of what it could be. maybe fuel filter, dirty injectors, to much oil on air filter. any help would be appreciated.

 

If the truck seems to be running fine, go back and hold your hand over the tail pipe. You may have a CAT problem.

 

Oil on an air filter can restrict airflow. I'd install a fresh new paper filter and see what happens.

 

I think, eventhough he didn't mention it, he is referring to a K&N fliter that gets washed, dried, and re-oiled.

I guess I will advise what always seems to come up first: Pull codes and see what comes up. You are probably looking at a dirty fuel filter, vaccum leak, or bad o2..... all of which cause bad mileage.

This is a "cut-n-paste" from another post I replied to (too lazy to type):

If you don't know the maintenance history, I would start there. I was surprised at the mileage, and power reclaimed by going step by step through all the standard stuff. IE - plugs, wires, coil, cap, rotor, pcb, filters (both air & fuel). Then there is the cleaning..... this is where I found most of my power loss. First clean all of the sensors (IAC, MAF, EGR, etc....) This will be a huge pain, but it is well worth it. Next start at the TB, removing the intake manifold and all. Chances are you will be amazed at the level of crap built up in the TB and down the runners. Don't forget to give a good scrubbing to the area where the EGR mounts. Mine was almost closed from the gunk in there. I mostly used TB cleaner/solvent that is safe for Fuel Injection + an old toothbrush and a pan to catch all the solvent and crud. If you still have some sanity left after all that, trace and replace all of your old vacuum hoses, the stuff is dirt cheap, and a leak will drive you nuts trying to track it down. I also replaced most all the fluids from the engine back to the diff. It took a while before all of this was done, but slowly it started to run better and better. Good luck to you.

 

These are some good things to look at. I have a 92 4.0 manual and one time it went from getting 15-17mpg down to around 4mpg! My dad works at a dealership and he pulled codes and found out it was the fuel-to-air ratio. I tried everything like a new O2 sensor, to some general maintenance under the hood. What it turned out being was the fuel pressure regulator, which wasn't really regulating anymore. I'm not sure on the specs, but I think it was letting through something like 70psi when it should be like 35psi. It ran fine, still had same power, but one thing that was also apparent was that the exhaust smelled really bad. I would say it was like eggs mixed with natural gas (if that makes any sense?). So don't rule that out as a possibility, since once I replaced that baby she went right back to normal.

Trev

 

i think i am going to take it to a dealer and have them pull the codes.

 

You can pull the codes yourself, see...pulling eec-iv codes... in the tech info thread at the top of the forum.