my gas mileage worsened after oil change on merc villager?

I recently had an oil change at wal-mart. The week before i had it changed i check my mpg and was getting 23 mpg average. Now I'm getting 17. My check engine light came on, the day after I had the oil changed, I called w-m and was told to bring it back. By the time I drove to the store the light was off and now I'm getting bad gas mileage.

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  • Anonymous
    1 decade ago
    Favorite Answer

    You need to get your engine computer checked for set codes. There should have been trouble codes set while the light was on. That could point to a problem. Maybe they knocked a sensor connection loose. Maybe it is a coincidence and a system is going out.

    You might call w-m and ask if they can, would do that for you. It is possible that they do not have anyone there qualified to do that. But they might just have someone who can. It takes special / specific knowledge and equipment to do.

  • my first question is if you changed oil weights. that would contribute to the fuel consumption. go back and have the check engine lamp checked out. even if the light is not on now, there is a code stored because of the recent activity. that would give you the most likely cause for the change in performance.

  • 1 decade ago

    Oil change has nothing to do with fuel economy. Obviously with the check engine light on, you have issues. I would find a reputable repair facility where you live and pay them to diagnose the problem for you. Most shops only charge one hours labor for the diag so it should only run around 100 dollars, from that point, the shop can give you an estimate to repair your van.

  • 4 years ago

    Oil is the blood in ur car n should b changed every 3000 miles, specially since it's from 1988. R u carrying lots of dead weight on ur truck? R u accelerating more than usual after a red light? Any truck/car/SUV w/ a proper tune-up will run better n increase ur gas mileage.

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  • 1 decade ago

    6mpg is a huge change in mileage...too much to just be oil...i recommend taking it to a reputable shop that isn't walmart have them tell you what the problem is and present walyworld with the estimate and tell them they need to pay for the repairs...Good Luck

    Source(s): 7 years in the business working on way to many cars
  • 1 decade ago

    Check your air cleaner and get yourself a bottel of STP Fuel injector cleaner.

  • Anonymous
    1 decade ago

    may be its not the oil check your air filter

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