3

I have a 2003 Ford Escape, 2.0L, manual transmission.

I am experiencing a very strange issue.

If I am driving (moving), and shift into neutral, the RPMs will rise up to 3500 about, and stay there till I come to a stop. I am in neutral the whole time. The car idles fine, but if I shift into neutral while the car is moving (while shifting between gears), or if I shift into neutral before coming to a stop, the RPMs rise much too high. But as soon as the car comes to a stop, the RPMs return to normal...

I replaced the idle air control valve, and throttle position sensor, and there are no engine codes. I did disconnect the battery after replacing the components, to clear the computer. No vacuum leaks that I can find either... I can't imagine the connection between wheel speed and idle speed..!!

Any ideas on where to start looking?

Thanks! Ben

UPDATE - RESOLVED - Replaced plugs and wires and issue was resolved.

Ben
  • 181
  • 1
  • 1
  • 8

4 Answers4

2

Im going to bet that you did not replace the IAC with a new Motorcraft brand. There is a large batch of aftermarket ones that are causing the exact symptoms you describe. You were probably correct in replacing it, but it needs to be a Motorcraft.

I had a 2003 Ranger with a high idle complaint. With bi-directional controls, I was able to command the duty cycle in 10% increments, and the expected behavior should have been a 100-150 rpm increase for each 10%. With the aftermarket IAC valves (note that a few different suppliers were used) the rpm would jump from 800 to 1500 rpms in the first 10% and then hold that higher rpm until 50-60% was commanded and then continued to rise. With the use of a labscope, I was able to verify the PCM's duty cycle was performing as commanded with the scanner, and a genuine oem IAC was indeed the fix.

Milison
  • 634
  • 4
  • 8
1

that definitely sounds like an interesting issue you have there. originally i was thinking that the vehicle was equip with shifting rpm hold and it was going on the fritz. but that seems unlikely. it doesn't sound like it would be a vacuum leak because it would idle at 3500 all the time. sounds software related to me. i would try to do a capacitor discharge. disconnect both battery terminals from the battery, wait a minute then touch both terminals together for a minute or two (WITHOUT CONNECTING THEM TO THE BATTERY). this will ensure a total reset of the computer. hopefully this helps, it has saved me a few times from some head scratching situations. best of luck to you!

Max
  • 146
  • 2
1

nothing special to re-learn, just drive normally. may be a little rough at first but will smooth out as the ecu re-learns adaptive values. shifting rpm hold is a new-ish feature on some models. i know the new manual mustangs have it. when you shift the computer will let the rpm drop to the next gear ratio and hold the rpm for a few seconds so when you release the clutch pedal it is a smoother shift

Max
  • 146
  • 2
0

Replaced plugs and wires and issue was resolved.

Ben
  • 181
  • 1
  • 1
  • 8