Idling Problems

[Hubes]

ok i am having some idling problems, especially when cold but usually all the time. my rpms will drop to about 500 then shoot back up to about 1k then soemtimes jump back to 500 and then back to 1k. i have reset the idle program many times per scott's instructions, got another maf sensor from fred which made the car seem smoother not rough idling any more, 02 sensorrs replaces over the summer, replaced the TPS last year, replaced Crank Position Sensor & Cam Position Sensor last april or may, replaced the iab last april. any ideas because it is awfully annoying. no CEL either. tomorrow i may put in a new bulb where the cel goes, just to make sure it isn't burnt out or anything. also i have conducted searches on this topic to find a potential remedy.

<small>[ January 21, 2003, 08:30 PM: Message edited by: Hubes ]</small>

 

[projectSHO89]

Although it is relatively new, I'd still suspect the IAB.

Steve

 

[Hubes]

think it needs a good cleaning? also if i were to have my intake fully dissaembled and cleaned completely (i have been told it it is wicked filthy and a full dissasemble will make it clean again) would this help? also i hope i do not have to buy another iab it was fairly expensive like 90$.

 

[sdpatt]

You can verify the CHECK ENGINE light is operable when you turn the ignition key to ON. No need to replace it unless it is dark when you do that.

The bouncing idle can be indicative of an IAB that has a faulty servo. This cannot be corrected by cleaning the flow ports. If you can substitute a known working IAB valve, that would determine if the IAB is the cause. Otherwise, O'Reilly, AutoZone or RockAuto.com all have replacements for around $50-$60.

Other possibilities are a throttle position sensor with a dead spot around idle or a vacuum leak. You may want to test the TPC for a linear output with no dropouts or just adjust it a tiny bit and reset the idle program to compensate for the new stop setting.

<small>[ January 22, 2003, 08:26 AM: Message edited by: sdpatt ]</small>

 

[Hubes]

scott,
how do i test the tpc's linear oitput and also how do you adjust it? once i do this i will reset my idle. i have your instructions memorized.

 

[projectSHO89]

With a multimeter.

Disconnect the electrical connector and connect your meter to two adjacent terminals.

Pull the throttle actuator and watch the meter reading. A good TPS will have a nice, linear resistance reading throughout the entire range of movement of the throttle.

This will catch gross failures. It is still possible that your sensor might have small flat spots that cause engine running problems.

A new sensor costs $24 at AutoZone, but only about $15 at Ford at part number F19Z-9B989-BA which is a recall kit that includes the sensor.

Steve