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Welcome to (or Ford 4L or Ford 4.0, whatever you want to call it.) I've been driving a 4.0 V6 OHV equipped Ranger for 10 years now and am very surprised at how little info there is on the net for this engine/vehicle combination. So I put up this site to let others know what I've learned. In those 10 years, I've also made some mods to my Ranger that would be good for any Ranger, Explorer or SportTrac with the 4L V6 engine, and I've included them as well.

Common problems and solutions:

  • Hesitation, sputtering, etc. - HOT!
  • Overheating
  • Bad Gas Mileage

  • Air Box Mod for 10hp - HOT!
  • CAI, Cold Air Intake- actual data
  • Mass Air Sensor
  • KN Air Filter
  • Exhaust
  • Headers
  • 160F-180F Thermostats
  • Stealth: Avoiding unplanned meetings with Officer Friendly.

    I bought the PVC fittings here.
    I bought some flex PVC pipe here.
    I bought my clone golf clubs here.
    I bought the headers & MAS here.
    I bought my truck tires here.

    What I believe & why:

    Disclaimer: This website is a Ford fansite. It is not authorized, nor endorsed by Ford Motor Company. No affiliatation or association exists between (aka and Ford Motor Company. All trademarks are property of their respective owner(s).

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    Bad gas mileage on the Ford 4.0L V6 Engine

    If your Ford 4.0 Ranger, Explorer or SportTrac is getting bad gas mileage, (usually around 8-12mpg in the city, down from about 16mpg in the city) it'll most likely be:

    a. Clogged air filter. Dump it in the trash and put in a K&N air filter. If you already have a K&N air filter, clean it properly, re-oil it and reinstall it.

    b. Replace the spark plugs if it's been over 40K miles since the last time they were replaced.

    c. Replace the plug wires if it's been over 80K since they were last replaced.

    d. Thermostat stuck in the open position. If the water temp guage never gets up to operating range, suspect the thermostat and replace.

    e. Replace the catalytic converter and redo the exhaust system in 2.5" pipe all the way back. You can also upgrade to a performance muffler (Flowmaster is what I use) and it will bump your power up, without hurting gas mileage. (Provided you can keep your foot out of it.)

    Of course there are many other reasons, but these are the most likely problems if you don't get a "Check Engine Light" (CEL.) If you get the CEL, most likely it's the O2 (Oxygen) Sensors. There are two, one on each exhaust manifold. They are about $70 each at most auto parts stores and not too hard to replace by yourself. Just have ramps or something to lift the truck in the air so you can get under it to replace them.

    Thanks for visiting