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-   -   My 4.0 is getting REALLY bad gas mileage! (http://www.fordrangerforum.com/4-0-sohc-4-0-ohv-tech/24673-4-0-getting-bad-gas-mileage.html)

Dildoyle99 01-18-2011 01:28 PM

My 4.0 is getting REALLY bad gas mileage!
 
I have a 99 Ford Ranger automatic with the 4.0. The tank is 16.5 gallon tank and im getting between 160 and 180 miles. My engine light comes on and i check it with my friends snap-on computer. It says its too lean. But the intake gasket isnt leaking. Theres no egr valve on it just need some help. Thank you.

TheStig 01-18-2011 05:15 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
check the intake tube between the MAF and throttle body
might have a crack or hole in it

dj224ranger 01-18-2011 05:38 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
clean your maf and check your sparkplugs and fuel filter or all the fuel lines for any small leaks

pooleo 01-18-2011 06:22 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
i wouldn't think lean would make you loose mileage...does it...? I had my o2 sensor wire drop on my front driveshaft once, it caused the left bank to run RICH, I was getting around 150 mile a tank, I pulled out the front plug and it was BLACK as coal!

maybe check your o2 sensors, just to see if one got snaged/broke

mickblock 01-18-2011 06:55 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
1999 you should have an EGR system. If someone deleted it, thinking that it's just for emission reduction then you could be getting mixture issues from that.

Dildoyle99 01-19-2011 09:15 AM

Re: My 4.0 is getting REALLY bad gas mileage!
 
when i hook it up it says it sucking air some place but cant find it. So ill try some of these and get back to ya. Thanks

satan 01-19-2011 09:41 AM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Quote:

Originally Posted by pooleo (Post 299735)
i wouldn't think lean would make you loose mileage...does it...? I had my o2 sensor wire drop on my front driveshaft once, it caused the left bank to run RICH, I was getting around 150 mile a tank, I pulled out the front plug and it was BLACK as coal!

maybe check your o2 sensors, just to see if one got snaged/broke

Lean codes set after the ECU has adjusted to the RICH limits (max injector pulse-width) and the o2 sensor(s) (position 1) are still showing lean mixture. In other words, fuel trim is full-rich = crappy mileage.

Dildoyle99 01-20-2011 12:36 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Well ive tried some of this stuff still nothing. Getting ready to swap maf sensor from friends truck to see if it helps. a friend was looking some stuff up and some other ppl said fuel pressure regulator? What bout fuel filter? It seems it may have a little loss of power. I dont know. Im averaging bout 9 to 10 miles a gallon.

FireRanger 01-20-2011 01:09 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
First your mileage needs to be calculated the right way before you can worry about that aspect. Fill the tank and reset the trip odometer. Drive until its just about empty. Refill the tank. Math: Miles driven divided by gallons pumped = MPG. Normal is anywhere between 16-19 depending on driving style and terrain.

Regarding the lean codes, this is usually caused by vacuum leaks, not a faulty MAF. Look for leaking, broken, cracked, or disconnected vacuum lines. The usual culprit is behind the engine under the spark plug wires. This is VERY common and costs a few mere dollars to fix/replace the bad line.

Fuel filter is cheap and easy so you might as well do it. But that isn't going to cause a lean condition.

Dildoyle99 01-20-2011 09:09 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
alright ill try to find that. Could i get a description of what the line kinda looks like. Thanks for the help

FireRanger 01-20-2011 09:17 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Just look for any vacuum line and the fittings they're hooked up to.

Dildoyle99 01-22-2011 06:44 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
i switched maf and it didnt seem to change it any. still bout 40 miles to a quarter tank of gas. My friend whose also got a 99 ranger said he thought his truck got a little worse gas mileage then usual. So ill check vac lines next week when i can get it on the hoist. im bout ready to go crazy, also it is actually running rich. Getting too much fuel.

FireRanger 01-22-2011 06:49 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Or you can read what I told you about earlier and probably fix it pretty quickly.... Not sure what you need to put it on a lift for to do this.

Dildoyle99 01-25-2011 07:08 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Checked vac lines. All good. Gonna try a fuel pressure regulator. hope it does the trick.

DiabloBlanco 01-25-2011 07:23 PM

Re: My 4.0 is getting REALLY bad gas mileage!
 
Any results yet?


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