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Engine Idling too high and sporatically

Discussion in 'Technical Chat' started by avatar525, Jan 25, 2011.

  1. Jan 25, 2011 at 8:10 PM
    #1
    avatar525

    avatar525 [OP] New Member

    Joined:
    Jan 25, 2011
    Member:
    #49941
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    First Name:
    Matt
    Springfield, VA
    Vehicle:
    00 Tacoma
    33inch Mud tires. 3 inch body lift. 2 inch suspension lift
    I recently got my 2000 Tacoma back from a repair shop after pummeling a deer with my front end. Thankfully there was no internal damage that they reported. It was just cosmetic. But 3 weeks after getting it back, my engine began to continually rev between 2000 and 3000 rpms. I first suspected a vacuum leak but couldnt find anything. I ended up replacing the Idle Air Control Valve and that took care of the revving problem.

    Unfortunately, now the engine idles too high. Around 1300 rpms when warm. 2000 when cold. Also if I get it up to high speeds and then put the clutch all the way in to take it out of gear. The idle stays at whatever RPMs it was at for a few seconds. Then drops to about 1000 and starts to rev itself between 1000 and 1500 rpms until I either put it back into gear. Or come to a stop. I have a feeling that I might need to replace the ECU but I'm not sure. Any ideas?
     
  2. Jan 25, 2011 at 8:15 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Moderator

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    FlimFlubberJAM
    Tenoe, AZ
    Vehicle:
    2013 Rubicon Unlimited,
    4.10 gears, sliders, and lots of buttons.
    Welcome to TW! Check the PCV valve. Also, double check all vacuum lines, and make sure there are no leaks in the intake track, and around the throttlebody.
     
  3. Jan 26, 2011 at 11:40 AM
    #3
    sadairk2

    sadairk2 Sexy Member

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    #48726
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    Peter
    Herndon, VA (NoVA)
    Vehicle:
    No truck - '90 300ZX TT
    Matt, I have a boost leak tester you can use to for sure eliminate that as a culprit. Hook it right up to the throttle body and it will tell you if you have any leaks in the intake.

    We don't think it's a leak since we've both looked. He has reset his ECU (disconnected the neg battery terminal for over 2 hours, just to be sure) and the issue persists. We would like to swap an ECU for a good one but this is new territory for us. What ECU models are compatible? It might be hard to find his exact truck at a junk yard or off a member. Thanks.
     
  4. Jan 26, 2011 at 3:57 PM
    #4
    BlueT

    BlueT Well-Known Member

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    I moded 1999 Taco so much it had turned to Land Cruiser
    Check your ECT sensor. On every Toyota this is what controls Idle Valve. with only addition of idle up when AC button is pressed. I would follow FSM and check ECT and wiring because this is most likely culprit. I had similiar problem on my LC and it was ECT sensor grounding itself and sending more voltage to ECU which in turn idle up.
    If all ECT items check out fine look for A/C idle up function.
     
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