My 2.3L 5spd manual Ranger idles at 1500 after intial start up, but after warming up it will not idle down until I come to a complete stop. I can be coasting in neutral to a planned stop and the engine will remain at 1500 rpm until I come to a complete stop. How does the engine know if the truck is moving or not? Once it idles down after that first stop its stays down.

 

Welcome to the forum

What year?

Rangers used two different 2.3l engines, (and 2019 Ranger uses a 3rd different 2.3l engine, lol)
1983-1997 2,3l SOHC Lima, 2001-2011 2.3l DOHC Duratec, (2019 2.3l Ecoboost)

If later model then its normal, idling under 1,000rpm is a big polluter, so to meet emissions requirements RPMs are held high until speed is under 5mph
Computer(PCM) is connected to speedometer, in some years it IS the speedometer

And in a later model manual vehicle the RPMs should hold high between shifts, so when you push in the clutch while moving RPMs should hold for a few seconds, this lowers emissions as well

 

So it could be tied to the spedometer. Its a 1989.

 

Yes, the 1989 should have a VSS(vehicle speed sensor) on the transmission/transfer case where speedometer cable hooks up

It was used for computer and cruise control if so equipped

But 1989 shouldn't have the hold idle high software, usually thats 1995 and up

So remove and clean your IAC Valve and replace ECT sensor, ECT sensor is a TWO wire temp sensor computer uses to set idle and CHOKE when engine is cold, it may not be "telling" computer true temp

Engine also has a Temp Sender, ONE wire, for the dash board temp gauge, they look similar but sensor use 5volts and sender use 12volts so not at all the same

 

I will do that. Thanks for this advice and thanks for the welcome to a great forum!

 

I have a 1997 ford ranger 2.3 and I can’t find out why but when I push in the clutch it stays at 2k rpms until I come to a complete stop and 1-2 seconds later it drops to 1k rpms and I don’t know how to fix this and it gets annoying at stop signs but I have cleaned the throttle body, changed the pcv valve, and the coolant temperature sensor because the truck temperature gage always says it’s cold so I thought maybe that the senor is saying it’s cold and making the engine idle high but no luck and it still says it’s cold what other senors might be the problem or vacuum leaks.

 

Welcome to the forum

That's an emissions requirement, and normal

Engines under 1,000rpms are big polluters, so computer will hold RPMs higher until speedometer is under 5MPH
BUT................
A 4cyl engine with manual trans should idle at about 750-800 when warmed up, 4 cylinders vibrate if RPMs are lower than that, V6 or V8 can idle at 600-650 without vibrations

After engine is fully warmed up let it idle and unplug the 2 wires on IAC Valve, it will close and RPMs should drop
RPMs should drop to 500 or so or engine may stall, either is GOOD

If RPMs do not drop then you may have a vacuum leak, or someone monkey with the Anti-Diesel screw on the throttle linkage
This screw "looks like" an idle screw, it isn't of course because every one knows you can have an idle screw with fuel injection, can't work
Locate the anti-diesel screw, while IAC Valve is still unplugged and RPMs are 1,000, turn it counter clockwise, unscrew it, if RPMs start to go down keep turning until engine is barely running, and its SET
Plug IAC Valve back in and RPMs should come up to 750-800

If turning the screw does not lower RPMs turn it back to where it was
You have a vacuum leak
Try plugging vacuum ports on the intake first, i.e. pull off a vacuum hose and plug that port with your finger, if RPMs drop that hose or its device has the leak
Start with Power Brake and PCV hoses