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Cleaned K&N - now bad mileage

Discussion in '1st Gen. Tacomas (1995-2004)' started by bcsteene, Jan 19, 2011.

  1. Jan 19, 2011 at 4:12 PM
    #1
    bcsteene

    bcsteene [OP] Active Member

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    3" Lift Magnaflow exhaust K&N FIPK intake
    So I just cleaned the K&N filter on my truck. Before I cleaned it I was getting 18-19 mpg. Now after I cleaned it I get 14-15 mpg. So I read about how K&N's can get the MAF sensor dirty so I cleaned that - it didn't fix the problem. The MAF was pretty dirty and old (120k), so I went and got a new one and put it on. Still getting 14-15mpg. What could be causing the bad gas mileage? Could the MAF be reading an increase of air and adjust the air/fuel ratio to pump more gas in to match the incoming air... if so is there a way to fix this?
     
  2. Jan 19, 2011 at 4:14 PM
    #2
    98tacoma27

    98tacoma27 is gooder 'en chicken Moderator

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    It could just be the ECU is relearning now that it's "slate has been cleaned". I would suggest monitoring it for a few more tanks and see what happens.
     
  3. Jan 19, 2011 at 4:20 PM
    #3
    bcsteene

    bcsteene [OP] Active Member

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    3" Lift Magnaflow exhaust K&N FIPK intake
    It's been about a month, and 4 tanks of gas. Still getting poor mileage. Tires have correct PSI, I'm using the same gas in it. Oil used is MObil One full synthetic... I'm not getting why the mileage would be so bad?
     
  4. Jan 19, 2011 at 5:25 PM
    #4
    747

    747 function > form

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    :notsure: maybe try disconnecting the battery for awhile, then reconnecting --> should 'reset' ecu. otherwise, could just be the winter gas mix...i think it's 'known' for such.
     
  5. Jan 19, 2011 at 8:18 PM
    #5
    ERIC

    ERIC Well-Known Member

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    have you ever changed any of the 02 sensors?
     
  6. Jan 19, 2011 at 8:21 PM
    #6
    08pretaco

    08pretaco Almost there

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    did you oil it too much?
     
  7. Jan 19, 2011 at 8:59 PM
    #7
    bcsteene

    bcsteene [OP] Active Member

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    3" Lift Magnaflow exhaust K&N FIPK intake
    I barely sprayed any oil on the filter, so it couldn't be that. No, I haven't changed the O2 sensors - could they cause this problem? I'll try the battery disconnect tonight and see if that helps, it is winter here too, and it's darn cold, so maybe winter gas: -1 right now and it's supposed to get down to -15 tonight!
     
  8. Jan 20, 2011 at 8:03 AM
    #8
    vantaco

    vantaco Well-Known Member

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    you over oiled it and the MAF now as oil on it

    take out the MFA and clean it
     
  9. Jan 20, 2011 at 8:29 AM
    #9
    ERIC

    ERIC Well-Known Member

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    it could just be the combination of cold and winter gas...but yes you have two 02 sensors one could be dead but normally the check engine light will go on.
     
  10. Jan 20, 2011 at 9:30 AM
    #10
    bcsteene

    bcsteene [OP] Active Member

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    No CEL. Does the engine computer adjust for the extra air coming in and raise the amount of fuel it sends to keep the air fuel ratio the same?
     
  11. Jan 20, 2011 at 10:06 AM
    #11
    ERIC

    ERIC Well-Known Member

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    well normally u get better mpg with a cai but then i have heard bad things about kn cai's....I have a afe and i got better mpg. all i can say is return it to stock or maybe take it in and see if the maf is working correctly
     
  12. Jan 20, 2011 at 12:19 PM
    #12
    bcsteene

    bcsteene [OP] Active Member

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    3" Lift Magnaflow exhaust K&N FIPK intake
    I have maf cleaner, I heard that another way to clean the maf is to soak it in isopropyl alcohol for abou 15 min. Any ideas on this?
     
  13. Jan 20, 2011 at 12:37 PM
    #13
    ERIC

    ERIC Well-Known Member

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    Na i never heard that...look around on here tho. Wen mine got dirty i took it to the dealership for a clean. It was like 50 bucks but i wouldnt wanna mess it up cause its like 400 for a new one.
     
  14. Jan 20, 2011 at 12:42 PM
    #14
    mjp2

    mjp2 Living vicariously though myself Moderator

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    This.

    And this.

    Use MAF cleaner so you don't leave any residue which would result in exactly what you're experiencing now.
     
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