Extremely Bad Gas Mileage

[LAFFlyBoy]

the filter on mine was on the frame under the driver's seat, it is an inline filter.

I had issues with my 89 with the 2.9 engine this last fall, i was getting about 14 mpg which two years ago it was geting around 24mpg, but it now sounded a but like a diesel (with at little imagination) but it turned out to be ill lubed Lifters and a rounded cam shaft. I have 167,000miles on mine, how many you got?

 

[cocoasranger]

yea id like details on the vaccum teat as well and im goin to autozone now for a fuel filter ...my tank is a 17 gallon tank and it does it on everyone... it will be on 1/4 and when i put $10 in it at 2.04 a gallon which is roughly 5 gallons it reads full on the gauge .....

If your gauge is reading 1/4 when you fill the tank, and it only takes 5 gallons to make the gauge read full, then the gauge is wrong and should be reading slightly less than 3/4 on a 17 gallon tank. 4 1/4 gallons times 4 = 17 gallons. Therefore 5 gallons down would translate to a little less than 3/4 full.

However, the fuel gauge sucks as much as the stock oil pressure and water temp. gauges and can't be relied upon much.

 

[IRKillroy]

When you let it idle to get warm in cold weather, you loose a good amount of gas because of the rich setting for so long. Did it only do it this one tank, or all the tanks since then? When I idle my truck a lot while I am working on it, it get around 160 miles per tank(tank for my being 11 gal). Could be a stuck injector, but you usually can feel that. Check the FPR on the fuel rail, that could be a likely cause and if it is then it could be going in the brake booster/ into the intake manifold.
Nick

you lose less letting it idle to warm up than you do driving it until it does.

hell ford even recommends you to idle it 5 min before you drive in cold weather in order to save fuel and prevent wear in the engine and transmission (auto) because it gets all the fluids up to a better temp before you stress the engine.

 

[jaymegriffiths]

you lose less letting it idle to warm up than you do driving it until it does.

hell ford even recommends you to idle it 5 min before you drive in cold weather in order to save fuel and prevent wear in the engine and transmission (auto) because it gets all the fluids up to a better temp before you stress the engine.

+1 I believe IR is right. When I drive right after starting, it burns way faster. letting it warm up for about 5-10 minutes burns very little gas and increase economy. However, if im goin to the store 3 minutes away im not gonna let it idle thats just dumb. I believe the OP's problem has little to nothing to do with not idling. my guess is either bad sensors (o2 or cat) or bad spark. Injector cleaners works miracles.(Did on mine at least)

 

[IRKillroy]

yeah... imagine this, your truck having your injectors on max duty cycle for the 5 min + it takes for your engine to get over the 90 degrees it take to go in closed loop... now, think of your driving pattern... do you keep it under 2k the whole time you drive?

now, imagine your truck idling (where it's supposed to at 750rpm) for 5 min at the injectors max duty cycle... and it just idles...

now where as it took probably half a gallon for it to warm up while driving, the idling took less then a quart...

and before you go saying that the higher the RPMS the faster it heats up, think about the physics of it... heat will transfer from the explosion in your combustion chamber to the steel of your block/heads at a certain speed, and from the steel to the coolant at a certain speed...

3k rpm will only produce the max temp for a longer period of time and increase the rate of energy transfer at a small double digit %, so the fuel savings is definitely not there.

 

[Beastly88]

i usaully let mine idle too but not more then 5 mins ...