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.

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

check the intake tube between the MAF and throttle body
might have a crack or hole in it

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1996 XLT 2.3T "White Lightning" 5/7 dropped, Turbo street toy
2006 FX4 Off Road, DD, work in progress
1985 XLT 2.8L 4x4 "The Black Pearl" (retired but still around)
1987 XL 2.3L 2wd R.I.P.

clean your maf and check your sparkplugs and fuel filter or all the fuel lines for any small leaks

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work in progress is an understatement
93 ranger xlt 4.0 (splash tribute)
4/5 drop, 17" mustang bullitts, shaved handles and emblems, 1991 Cadillac tail lights, black lights with hids, ect....
mods in progress:
custom interior, 00 mustang gt trac lok and rear discs, 95-97 front spindles and brake upgrade, c notch, paint

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

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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.

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08 4.0 Sport 4x4
Stock

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

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

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.

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'01 XLT Ext Cab 4-dr / 4.0 / 5R55e / 265-75x16 / K&N FPIK / & many unknowns

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.

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

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.

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(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

alright ill try to find that. Could i get a description of what the line kinda looks like. Thanks for the help

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

Just look for any vacuum line and the fittings they're hooked up to.

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(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

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.

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

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.

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(Formerly)
FireRanger
2003 Edge 4.0 4wd

How to: Aux light wiring, relays, & fuses
Info: 300+ intake threads here on FRF
Info: HID Projectors
How To: NO HEAT Troubleshooting Guide

Checked vac lines. All good. Gonna try a fuel pressure regulator. hope it does the trick.

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1999 Ranger xlt 4x4
Chrome Pacer wheels with 30x 9.5 Nokian Vativa MTs

Any results yet?

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