Hanging At 2,000 Rpm

Discussion in 'Fox 5.0 Mustang Tech' started by Strype, Jul 12, 2013.

  1. B303, GT40X, 5 speed
    Hey guys this car is still hanging at 2,000 RPM for 10 seconds when out of gear then returns to idle. Every now and then it searches to 1500. Here's what's been done recently -

    TFI Module, Plugs, Cap, Rotor button, Idle Air Bypass, TPS, Coolant Temp Sensor. These are all brand new. The TPS is set at .98. I did adjust the idle screw and it sits mostly at 1,000 rpm when warm. Until it's warm it tries to idle down to 600-700. Otherwise it runs great. That B303 does NOT like to idle under 900.

    Question - Isn't there a sensor on the brake and a neutral safety switch somewhere? Could that be causing it to hang? Could it be the throttle linkage?

    I will go back through the surging idle checklist as well. I'll look at that now.
  2. Did you reset the computer after adjusting the idle set screw? That can sometimes cause what you are seeing because the car learned how to idle..and now you've confused it.

    Perform the idle reset by unplugging the IAC and spout and adjusting the idle set screw to a low idle. This will be tough with a bcam but it should still idle. Then reset the computer, plug the IAC and spout back in and let the car relearn idle. Afer this part, do not touch the idle screw unless you reset the computer or it will cause some issues with hanging idles or high idles
    jcgafford likes this.
  3. Okay I'll try that. Thanks
  4. I guarantee your problem is a failing connection at the 10-pin connectors clipped to the back of the intake throat. Take them apart, clean them with MAF cleaner, then carefully tweak each individual pin so it makes a tighter fit with its mate on the other side of the connector. Reconnect and disconnect the connectors a few times so you get nice clean contacts, connect them one last time, and be done with it.
  5. I know this is a really old post but I am still having this issue. I haven't driven my mustang in literally a year. My Focus ST met with a deer Friday, and now I need my stang.

    The hanging idle isn't so bad as the POPPING OUT OF THE EXHAUST. This has to be timing related but it's sitting at 14 or 16.

    I will try that tonight kind sir!

    Any other ideas are welcome. My friend suggested the grey insert pin that goes into the distributor may be to blame?
  6. By all means, check and clean the 10 pin connectors as a simple first step.

    See the graphic for the 10 pin connector circuit layout.

    Hanging idle problems are a symptom of TPS trouble. Try unplugging the TPS sensor before starting the engine and see if the problem disappears. This will probably set the CEL (Check Engine Light) and set a code in the computer.

    Just in case you lost the link to the Surging Idle Checklist, here it is again...
    Do the "Surging Idle Checklist , it will help you find and fix the problem easier.