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Thread: Terrible MPG

  1. #21
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    One other thing, have you checked your cats?
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  2. #22
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    Put some in gas tank and the rest in the brake booster valve. Let the engine die and then try to restart. Be sure to change the oil within a few days.
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  3. #23

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    how do i check my cats? sorry i am a newb i just started into cars. im 16 and the only one in my family that has an intrest in this.

    and for the seafoam i thought u only needed to change the oil if you put it in the crankcase?

  4. #24
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    If you put it through the brake booster, I would change the oil as well.

    In all honesty, one of the quickest ways to check cats, is to take them off and use a leaf blower on them. If they don't have much air going through them, you know they are plugged. But I would assume, that if they have never been swapped and you are high on mileage, they may need to be changed out.
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  5. #25

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    it has a custom exhaust but im not sure if they changed it or not. thanks for the info. ill check into that. is there any signs of it being clogged by driving it? like poor idle or anything like that? because it starts great, idles good and everything. my only problem is the MPG that doesnt make sense

  6. #26
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    Symptoms vary from vehicle to vehicle really.
    Black Bear Performance- Custom Tuning Solutions

    Authorized EFILive and MAGNACHARGER seller

  7. #27

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    If you run seafoam just in the crankcase (I ran through TBI/Crankcase/Gas tank) you must change that oil. I forgot to take a picture, but after about 40 miles I took my truck to have the oil changed even though I JUST had it changed a month ago. They caught some of the drain off and the results were oil that was as black as the night, it was amazing to see that.
    ----------------------------------------------------------------------------------------------


    Vehicles owned:
    1995 Chevy Cheyenne 4.3L V6
    1972 Chevy C-10 (on storage lot, fathers but part of the family chevys!)

  8. #28

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    another thing is that when im driving on the highway and im crusing at say 65, if i want to go faster i have to just about almost push the petal to the floor till i actually feel some get up. any suggestions?
    i have 103miles on the truck

  9. #29

    Default

    Check EGR valve. I use to have the exact same problem. On the interstate, going 65-70 I'd literally stomp the pedal to the floor for weak acceleration. Be sure to check the fuel filter as well.
    Last edited by liquidmetal; 01-31-2010 at 09:01 PM.
    ----------------------------------------------------------------------------------------------


    Vehicles owned:
    1995 Chevy Cheyenne 4.3L V6
    1972 Chevy C-10 (on storage lot, fathers but part of the family chevys!)

  10. #30

    Default

    but if it was clogged wouldnt the engine light come on? or would it not?
    i havent had that light come on once since i bought the truck

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