Hello, I have a 1990 Ford Ranger 4.0 Litre which is getting horrible fuel milage. Im Currently getting about 9 City, and 15-16 Highway. There was a check engine light so i checked everything and found that was a dirty MAF sensor and i cleaned it with some throttle body cleaner, along with spraying the rest of the can into the intake manifold to try and get rid of any other dirty parts. The light went off and i still get poor milage. I changed the idle control valve also because when the MAF was dirty the engine would "hunt" for an idle speed(once i cleaned the sensor that problem went away). Does anyone have any idea what would give my engine this problem and what i can do to fix it?
I was thinking I have to buy a new MAF sensor, but when I used a scan tool nothing came up on the screen for problems.

Sincerly,
FastEdsel

 

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It sounds like you cured the MAF problem already, no sense dropping the bucks on a new one at this point.

You've already done the things I would have checked first. Have you run any fuel injector cleaner through the gas tank? How's the ignition system? Have you pulled the plugs to check them? How's the air filter?

Also, I'm wondering if this is a new problem that suddenly came up for you or if it's been going on for a while. How long have you had the truck and what kind of mileage were you getting before?

Did you do any mods like big tires, a bulky camper shell or anything like that?

Did you put a new, noisy exhaust system on it? This can result in decreased mileage simply because the driver tends to get a bit heavy on the go pedal, enjoying the sound of the new pipes. It tends to be self-correcting after a while...

 

When was the last time you changed your spark plugs,fuel filter, air filter,pcv valve and checked for air pressure in your tires? these would play a roll on your fuel consumption for the better

 

It sure would have been nice to know what the code was. Along with everything else noted, be aware that when you spray cleaner into the intake large amounts of that crud lands on the spark plugs; this dirty crud can form a conductive coating on the plugs that weakens the spark, lowers mileage, reaults in poor idle, and of course, lowers performance. Lastly, is there any black smoke comming from the tailpipe, especially when idling?

 

Hey, everyone i think i have finally found out the problem. Since i just started taking a automotive apprenticship i figured i should check the spark plugs out, having some spare time during break. But to my already assummed guess they were all good. But when i went to put the first plug back in, i wass just about to lean over the fender and the end of the spark plug leterally fell off. So i replace all the old motomaster spark plugs with some autolites from Napa. Wow what a difference! It runs smoother, starts better and has more power. Now im getting about 23mpg highway, but not to sure on city use yet. But when i first took out the old plugs the tips were completely white.... I asked some friends and they said that means my engine is running hot. I thought this is kinda strange since its been about 23 degrees celcius below zero here latley. Anyways thank you all for your help!

FastEdsel

 

White tips = lean condition in the engine...I believe if memory serves correct.

Not much to do with the outside environment, really.