its a 2001 5 speed 4.7 dodge dakota. iv noticed when im slowing down for a stop sign and push the clutch in the rpms bounce like crazy and the truck rattles like its about to shut off but then the rpms bounce back up and down untill im at a stop then its a fine idle.
It could be a dirty IAC (idle air control) or possibly the TPS sensor.
Mine did just that when I changed the TPS sensor with an aftermarket
one that turned out to be bad right out of the box. The idle fluctated
and dropped down to stall eventually because the idle rpm had
dropped too low. As long as I kept the revs up, it would idle above
1000 rpm. I put the original TPS back on an it fixed the fluctating
idle problem. The defective sensor was returned for credit.
If it's fluctating like this Durango...check the TPS sensor on the throttle
body too. These are easy to check with just a cheap digital voltmeter
while the TPS sensor is still connected to the throttle shaft on the vehicle.
Fluctating idle rpm tach needle symptom.
http://www.youtube.com/watch?v=c-f0bCcQ63o
1. Back probe the center wire (o/p of TPS sensor) with the positive
probe of the voltmeter. (dig the point of the test probe into the insulation
of the centre wire on the connector still plugged into the sensor.)
2. Find a good engine or battery ground for the negative.
3. Remove throttle body air duct.
4. Turn on ignition key BUT do NOT START ENGINE!
5. With the voltmeter hooked up to the TPS sensor on the throttle body,
and the voltmeter DC volts set to 20vdc; (this is a 5volt sensor)
read the CLOSED THROTTLE POSITION;
it should be 0.50 volts dc
as you slowly move the throttle plates (using the accelerator cable lever
on the throttle body, on the engine....the dc volts should rise smoothly
as the throttle plates start to open to a maximum of 3.80 to 4.5volts DC
at FULLY OPEN THROTTLE.
IF the throttle plate/TPS sensor output transition is not smooth, between Closed to mid throttle valve positions, the TPS sensor could be bad,
giving the PCM a hard time to keep the rpms at idle steady.
