Possible causes for poor gas mileage?

[JDR]

Hey guys, I have a 91 Ranger 4X4, wondering if anyone has any experience with poor gas mileage. I am filling up and getting only about 360 km to a tank, I am also getting a constant high idle. Any sensor that usually goes possibly? Thanks, Jay

 

[Dweano]

I'm only getting 400kms to a tank, but I do have 7 inches of lift, heavy 33's and 3.73s.
First off: Tune up: fluids, filters, plugs, etc.
Second: I had a stuck open thermostat and I got that fixed and there was a noticeable MPG increase, I also got the tranny fluid flushed and I think that helped some
Third: Check Engine light?

 

[nitrofan1]

Got a couple of hours? LOL

Seriously, I get that question a lot every week at work. Here's what to factor in: 4x4, OLD, probably a lot of miles so the engine tends to loosen up on tolerances, tune up, fuel injection cleaning, multiple sensors old and worn out.

Take your time and work it over. You probably won't get a big increase but every little bit helps.

 

[wowslamtrack]

Keep youre foot out of the injectors led foots lead to poor gas mileage , also its a 4.0 only .6 liters from the v8 model that ford produces so its a bit engine . The main reason though is the fact of what ever your engin is turning at any given speed IE: if ur running 70 mph and youre engines turning 3500rps thats using quite a bit of fuel and getting about 17 mpg, to prove this theory i used to have a 97 camaro with a 6 speed and a 5.7 and running 72 mph she was only turning 1,100 rps and i was almost get 30 mpg reason being that the gear ration was so Low in 6th gear she dident have to turn much to maintain that speed , (no joke) if you want better gas millage reduce ur speed or enhance ur gears for lower ratios ones this will make you slower but help out, also the old theory "easier the air comes in and goes out the less the truck has to work to move" get a air intake (cold air preferably just not to low in the fender if youre mudding ) and get a better exhaust.

 

[feellnfroggy]

The 4.0 actually gets better mileage than the smaller motors, most of the time. But I would run some seafoam or injector cleaner of your choice through it. Check your plugs and wires, the plugs are prolly gettin wore down. Do some general maintenance on everything and make sure its got good air filters, fuel filters etc.

WOWSLAMTRAK, dont get these guys started on cold air intakes. Its a fight you cant handle Lol. btu a clean air filter is a good idea. Maybe remove the intake silencer on your truck, and run a scan of all yuour emission equipment too. EGR etc.

 

[Big Jim M]

Well, yeah!

Keep youre foot out of the injectors led foots lead to poor gas mileage , also its a 4.0 only .6 liters from the v8 model that ford produces so its a bit engine . The main reason though is the fact of what ever your engin is turning at any given speed IE: if ur running 70 mph and youre engines turning 3500rps thats using quite a bit of fuel and getting about 17 mpg, to prove this theory i used to have a 97 camaro with a 6 speed and a 5.7 and running 72 mph she was only turning 1,100 rps and i was almost get 30 mpg reason being that the gear ration was so Low in 6th gear she dident have to turn much to maintain that speed , (no joke) if you want better gas millage reduce ur speed or enhance ur gears for lower ratios ones this will make you slower but help out, also the old theory "easier the air comes in and goes out the less the truck has to work to move" get a air intake (cold air preferably just not to low in the fender if youre mudding ) and get a better exhaust.

Slam in that camero you had more horsepower to push it along.. Using the sixth gear was plausable at hiway speed. HOWEVER our little rides are using all the torque and horsepower they have...almost every minute. Lowering the rpm causes the skinny pedal to go to the floor, which in turn retards the timing and richens the mixture. The result of which is far WORSE milage.
The opposite is true in low powered vehicles. More rpm, up to a limit of course, causes a lean mixture and increased timing. THIS is where we get the best mpg.
As for changing the intake... as designed the engine gets ALL the mixture in the chamber it can handle. ANY more mixture and the valves would clatter from too much compression.
THIS should be PROOF that the aftermarket intakes don't do one damn thing for the engine..all they do is to make more noise! If they actually did what the advertising says your engine would clatter form the moment the silly thing was installed.
Big Jim