garbage fuel mileage

[yewwoodtree]

so im getting around 10mpg city/highway no matter how easy i am on the pedal. I got a 1990 ranger xtra cab 4x4 2.9 standard trans. I am running 32 inch tires with 3.73 gears but i think it still should be better. Ive swapped the engine twice and ever since i swapped it the first time the mileage has been bad. I have modded the air box by taking it out and putting a cone filter on the end of the rubber tube. And the vacuum line going into the box i have plugged. The fuel pump is also making weird sounds when i turn the key forward like its about to crap out. Do you think its a bad ground, sensors, or fuel system problem. The engine swapped into it is of the same year and runs perfectly.

 

[Strieg]

Have you checked your o2 sensor? I'd check that first, since it's pretty easy to get too. As for the fuel system... Do you have any other issues? Like stalling sputtering or anything?

 

[yewwoodtree]

as far as i know the o2 sensor is original how would i go about checking it, just replace it? It dosent stall or sputter at all

 

[Strieg]

Eh I'd just replace it. From what I remember there not too expensive.
None of the mods you listed should cause a drop that low in mileage. It doesn't seem like a fuel system prob, because if your fuels restricted by a bad pump or filter you'd stall or sputter when you get on the gas from the restricted flow. I would say do a tailpipe swipe and see if there's black residue there, that usually indicates a rich fuel environment which results in poor fuel mileage. But that could also change depending on your cats...
That said, you might want to check on your cats.

 

[gaz]

Cone air filter

Hey "yewwoodtree",
When I removed my stock airbox and ducting loaded with a "stock replacement". K&N and it made my ECU think it was constantly in warm-up mode (dumping in extra fuel to compenste for the cold air readings). I went trough everything I could think of to correct thethe milage drop, when I changed the air intake set-up back to the stock box/ducting/K&N minus the flat intake reducer on the lead of the ducting (passenger side, just inboard of the head light, next to radiator outlet).