Thread: Mileage...

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  1. #1 Mileage... 
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    I know there are tons of posts about fuel mileage, but I'm so confused. My car must be burning really rich because I am a light footed driver, and I am getting 13 mpg. I can smell strong gas from my exhaust seconds after startup. How do I improve on this stuff? I have a 2000 Grand Prix GTP.
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  2. #2 Re: Mileage... 
    GTP Level Member Impala131's Avatar
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    First, check for any CEL lights or anything obviously wrong. Make sure your tire pressure is high enough. Also, are you running your A/C? That can hurt your gas mileage as well. If you're using your DIC to calculate gas mileage, don't forget to reset it. Also, going 60 on the expressway gets you better mileage than going 70 or higher. I can generally get 35MPG highway, 17MPG city (I like to take off from lights once in a while so you can probably do better.) I think the biggest key is maintenance.
    2003 Grand Prix GTP.... the journey begins again....
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  3. #3 Re: Mileage... 
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    I drive very light in the city, and get 13... My SES light is on, only with the gas cap code. Everything else is fine. Replaced MAF, CAI, new plugs and wires, idk what to do...
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  4. #4 Re: Mileage... 
    GrandPrix Junkie gtpeddie's Avatar
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    with out the gas cap on correctly pressure is not building up properly and fumes could be escaping witch is fuel

    97 GTP DD, 1952 Ford F-1 Resto Project, 2006 Mustang GT "UnDeR CoNsTrUcTiOn", 02 GPGT SOLD!, 98 GTP Parted/Scraped
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  5. #5 Re: Mileage... 
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    It's been happening even before the gas cap code has been on though
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  6. #6 Re: Mileage... 
    GrandPrix Junkie gtpeddie's Avatar
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    i was just thinking im really not to sure just throwing out my opinion

    97 GTP DD, 1952 Ford F-1 Resto Project, 2006 Mustang GT "UnDeR CoNsTrUcTiOn", 02 GPGT SOLD!, 98 GTP Parted/Scraped
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  7. #7 Re: Mileage... 
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
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    What brand plugs?

    Ever thought about new o2 sensors?

    SMGPFC Member #1
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  8. #8 Re: Mileage... 
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    I have a new O2 sensor in my 3" stainless steel ZZP downpipe with cat, and I'm using the stock ACDelco Iridium's.
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  9. #9 Re: Mileage... 
    Killa Bee Scottydoggs's Avatar
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    Quote Originally Posted by mick777wauchope View Post
    I drive very light in the city, and get 13... My SES light is on, only with the gas cap code. Everything else is fine. Replaced MAF, CAI, new plugs and wires, idk what to do...

    you could have a bad evap or purge solenoid, i think thats what its call, if a new gas cap dont fix it.

    if you dont hit the highway much or at all, and drive around down all the time, like me, so mine drops as low as 12 mpg on the mpg average. even tho the instant it always up over 25 or higher. and im not hot rodding around town. pretty light on the gas myself.

    98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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  10. #10 Re: Mileage... 
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    if i replace the purge solenoid, will i get better mpg?
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  11. #11 Re: Mileage... 
    Killa Bee Scottydoggs's Avatar
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    i really have no idea if it would affect your mileage but smelling gas is no good.

    98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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  12. #12 Re: Mileage... 
    Killa Bee Scottydoggs's Avatar
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    or buy a 15 dollar gas cap and see if that fixes it.

    98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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  13. #13 Re: Mileage... 
    GXP Level Member Tuner-Extraordinaire's Avatar
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    run a seafoam?
    Whine with your Cheese?
    Stock+Self Tuned. Going for low 14's everyday.
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  14. #14 Re: Mileage... 
    GTP Level Member Rico's Avatar
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    Fuel smell from tail pipes?
    That's not normal, especially if you have a catalytic converter.

    Pull the oil dipstick and see if it smells like fuel.

    You may have a dead injector but this should set a misfire code P030X. X would be cylinder number 1-6.

    You said you put a new O2 sensor? Seems like you replaced the down stream sensor. How about the upstream sensor that is in the rear manifold?
    It's a CUMMINS Dodge not a Dodge Cummins
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  15. #15 Re: Mileage... 
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    Quote Originally Posted by Rico View Post
    Fuel smell from tail pipes?
    That's not normal, especially if you have a catalytic converter.

    Pull the oil dipstick and see if it smells like fuel.

    You may have a dead injector but this should set a misfire code P030X. X would be cylinder number 1-6.

    You said you put a new O2 sensor? Seems like you replaced the down stream sensor. How about the upstream sensor that is in the rear manifold?
    How much would that o2 sensor cost? Is it easy to replace?
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  16. #16 Re: Mileage... 
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    I have replaced the gas cap, and Im scared of running seafoam through my gtp because I don't wanna strip the rotors. I have ran it through gas though.
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  17. #17 Re: Mileage... 
    GTP Level Member Rico's Avatar
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    Quote Originally Posted by mick777wauchope View Post
    How much would that o2 sensor cost? Is it easy to replace?
    Sensor isn't that expensive $50...really easy to change.
    It's a CUMMINS Dodge not a Dodge Cummins
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  18. #18 Re: Mileage... 
    Donating User Swiggles's Avatar
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    i dont recall the 2000 having the gas cap code. what is the exact code number you have.

    ive noticed alot of people check codes and have it be emissions related and just brush it off as a "gas cap code" when it has nothing to do with the gas cap.
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  19. #19 Re: Mileage... 
    GTP Level Member indygrandprix's Avatar
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    I'd run a scan tool thru it and check your long term fuel trim. If your o2 sensor is bad and it reads lean it will cause the engine to add more fuel. It can be up to almost 20 off before it will set the check engine light. it should be around 10 or less preferably
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