I have a 2002 2.3 auto. It idles @ 1000-1100rpm. It will not adjust down any lower. BUT, when I am coming to a stop or coasting and I put it in neutral, the idle will drop to 6-700 rpm until I come to a complete stop. At complete stop it immediately returns to 1000 rpm. So, I know this vehicle will idle at a lower rpm, how do I get it there? Screw adj. on throttle body will not do it.

I scanned forums for some answer or indication of what it might be, no luck so far.
What is it about the ranger that would make the idle lower when it is rolling in neutral and go back to 1000rpm as soon as it stops? Lower by 3-400 rpm?

 

I might just have the same issue...

 

check pcv valve it will cause a high idle and not throw a code.
also IAC and possibly VSS

 

mine does the same thing. someone stated emissions. but stop at an intersection, put in neutral and coast downhill. the idle picks up on mine. when i stop in drops back down. the iac must be connected to the speedometer. i would like to figure this out

 

see my post #3 just above. 1st thing to try though would be disconnect the negative terminal on the battery for 1/2 hour or so then reconnect in order to re-set the computer.

 

Ok so Kim's issue is: Idles at 1000 RPM at a complete stop. If coasting then idle drops to normal until stopped then when stopped idle jumps back up again.

Tim's issue: Idles normal. If rolling to a stop then idle stays 1000-1200 RPM until stopped. When stopped then idle returns to normal. This sounds more normal.

These two have very different symptoms.

Kim: Here are some things to check:

1. As has been said already, it could be a vacuum leak via the PCV valve. This valve is located on the driver's side of the block and is very hard to get to but it can be done. Or it could be a vacuum leak somewhere else.
2. The problem could also be that the IAC solenoid is gummed up with oil blow-by. Removing and cleaning the IAC with some sensor safe spray cleaner could help.
3. It could also be a gummed up MAP sensor. This too gets covered in old oil blow-by deposits and may need cleaning with some sensor safe spray.
4. Do not adjust the screw on the throttle body. This is only to be used as a hard stop for the throttle blade so that it doesn't bind in the throttle bore.
5. Throttle cable is binding causing the throttle blade to be open to far.
6. The TPS sensor on the throttle body could be bad. Replacement is pretty easy.
7. The VSS sensor could be bad but I really don't see many, if any posts on these going bad.

And so I'd try what 97ranger said first. Disconnect the negative battery terminal for 30 mins, then reconnect and let the truck idle for 15 minutes (idle is relearned in a 15 minute idle). If nothing changes then, while the engine is running disconnect the wire from the IAC. If the engine stalls or almost stalls then you probably don't have a vacuum leak. If the engine continues to idle but slower then you have a vacuum leak somewhere.

Known vacuum leak sources:
- PCV
- IMRC solenoid hoses crack.
- Front of the intake manifold just behind the power steering pump there is a small plug for the IMRC flaps rod. This plug can come out. Same with the back too I believe.