1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

cleaning iac valve / misfire

Discussion in '1st Gen. Tacomas (1995-2004)' started by boodacrf450, Jan 12, 2024.

  1. Jan 12, 2024 at 6:40 AM
    #1
    boodacrf450

    boodacrf450 [OP] Well-Known Member

    Joined:
    Jan 9, 2024
    Member:
    #441260
    Messages:
    52
    Vehicle:
    99 Tacoma 2.4L
    hi again will cleaning the iac valve help stop misfire I have replaced plug and wires did compression check and only intermittent get p0301 code. I'm cleaning iac valve and throttle body any other ideas of what might cause random misfire?
     
  2. Jan 12, 2024 at 6:49 AM
    #2
    TenBeers

    TenBeers Well-Known Member

    Joined:
    Jun 5, 2009
    Member:
    #18067
    Messages:
    7,710
    Gender:
    Male
    First Name:
    Rich
    Bentonville, AR
    Vehicle:
    2018 TRD Pro Cavalry Blue
    Yeah.
    What engine do you have? You could try swapping ignition coils around and see if the misfire moves with it. Along with proper compression (which it sounds like you checked), you need air, fuel, and spark. Air issues usually don't just affect one cylinder, but I guess it could happen. So, fuel and spark would be next. Ignition coils, wires, plugs for spark. Fuel pump and injectors for fuel.
     
  3. Jan 12, 2024 at 6:58 AM
    #3
    boodacrf450

    boodacrf450 [OP] Well-Known Member

    Joined:
    Jan 9, 2024
    Member:
    #441260
    Messages:
    52
    Vehicle:
    99 Tacoma 2.4L
    99 tacoma 2.4l 441000 miles compression was.good I replaced the coil.pack on 1,4 but still random misfire
     
  4. Jan 12, 2024 at 7:18 AM
    #4
    TenBeers

    TenBeers Well-Known Member

    Joined:
    Jun 5, 2009
    Member:
    #18067
    Messages:
    7,710
    Gender:
    Male
    First Name:
    Rich
    Bentonville, AR
    Vehicle:
    2018 TRD Pro Cavalry Blue
    Yeah.
    Does it misfire just at idle, like a stumble, or at all RPM's? If just at idle, you may be on to something with the IAC, but I would still expect the misfire to move around a bit. The other major contributors to the spark side are the camshaft position sensor and the crankshaft position sensor. Cheap replacements can be found on RockAuto, but if that fixes it, I'd eventually replace with Denso.

    I don't have any specific knowledge on that engine, so I'm just spitballing here on what I would look at. After ignition, I'd look at injectors.
     
  5. Jan 12, 2024 at 7:42 AM
    #5
    boodacrf450

    boodacrf450 [OP] Well-Known Member

    Joined:
    Jan 9, 2024
    Member:
    #441260
    Messages:
    52
    Vehicle:
    99 Tacoma 2.4L
    just a idle and usually only.when it's cold.i already replaced all the injectors so I'm hopingit is the iac valve
     
  6. Jan 12, 2024 at 8:51 AM
    #6
    TenBeers

    TenBeers Well-Known Member

    Joined:
    Jun 5, 2009
    Member:
    #18067
    Messages:
    7,710
    Gender:
    Male
    First Name:
    Rich
    Bentonville, AR
    Vehicle:
    2018 TRD Pro Cavalry Blue
    Yeah.
    Yeah, that's where I would go if just at idle. Also check vacuum lines for old and cracked hoses, PCV valve, stuff like that. My old '77 Celica with the 20R had like 20 feet of vacuum lines and way too many vacuum switches.
     

Products Discussed in

To Top