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05 Tacoma Running Lean (P0171, P0174)

Discussion in '2nd Gen. Tacomas (2005-2015)' started by Syldee, Dec 22, 2023.

  1. Dec 22, 2023 at 8:13 PM
    #1
    Syldee

    Syldee [OP] New Member

    Joined:
    Dec 22, 2023
    Member:
    #440086
    Messages:
    1
    Gender:
    Male
    Vehicle:
    05 Taco 4.0
    Magnaflow cat back exhaust, K&N CAI, 2.5 inch Leveling Kit
    So I recently got my hands on my first taco (05 TRD OR), Got it from a buddy at a good price with some mods done to it. Long story short 5 months later I have replaced the headgasket, Wheels, coil packs, plugs, steering system, and a few other things. Last week I was on the highway right after getting it back from the mechanic (like 200 miles afterwards) and once the thing got to around 60mph the check engine light came on with the p0171 and p0174 codes. I've done quite a bit of digging through here and other spots online and was hoping to get some help as it seems these codes are very annoying to deal with. I have already gone the MAF route due to some stuff I saw about oiled filters messing with those things and no cigar.

    I fortunately was able to get my hands on a scan tool that allows me to view the live date of the truck running, what I've noticed is that my long term fuel trims go up as the rpms increase and at idle they are very close to being in "reasonable" parameters. 41 was the peak that I saw and 14 was the lowest I saw out of both banks. My thinking is that there is a vacuum leak going on somewhere that isn't obviously noticeable. Ordered me a decent smoke machine to do a check on the intake system to see if that's the culprit. While I wait for the thing to get here.....

    Has anyone else encountered anything similar in a 1GR-FE? and if so what was the fix?
     
  2. Dec 22, 2023 at 8:50 PM
    #2
    Dm93

    Dm93 Test Don't Guess

    Joined:
    Mar 3, 2015
    Member:
    #150066
    Messages:
    13,763
    Gender:
    Male
    Texas
    Vehicle:
    2014 DC OR 6spd 4x4
    Predator tube steps, Ranch Hand grill guard, Magnaflow CatBack exhaust, Toyota tool box & bed mat, 2LO Module by @Up2NoGood, Rearview Compass/Temp Mirror, Tune by @JustDSM.
    I'd check fuel pressure, with a vacuum leak you would typically see high positive fuel trims at idle and they would come back closer to 0 as RPMs and load increase.
     
    Syldee[OP] and TnShooter like this.

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