Howdy, I've got a 2011 ford ranger 2.3l and as I cruise to a stop the idle decreases to about 1100-1200 as it should due to emissions protocol. However once at a complete stop the idle continues to sit at 1100-1200 and sometimes even jumps up to 1500 or so before returning to normal idle around 800. This Typically takes about 20 seconds. I understand that it is normal to have a higher idle until under 5mph but it seems this feature is being incorrectly read by the computer. In my 1994 ranger I had this issue and replaced the speed sensor in the transmission and that fixed it. Which sensor is it in this model? I have had a difficult time uncovering this information. Thanks!

 

Welcome to the forum

2001 and up Rangers use the OSS(output shaft speed) sensor for vehicle speed, its on the rear area, mid-line or higher up, of the transmission, manual or automatic
Its a 2 wire sensor connected directly to the computer(PCM), computer has rear axle ratio and stock tire size to calibrate OSS signal to a true speed signal

I would clean the IAC Valve first, it could be hanging up when computer tries to close it
Also check CHT(cylinder head temp) sensor when slowing to idle, higher temp cause computer to run engine at a higher RPM until cylinder head cools down a bit

You can get a Bluetooth OBD2 reader for $15 and the Torque Pro APP for $5
With this setup you can see what the computer sees from all sensors
Works on ANY vehicle sold since 1996, not a Ford thing, good tool to have when there is a problem in newer vehicles
Also reads and clears codes of course

 

Thanks for the input Ron, i think it was your original post that helped me diagnose my old 94 speed sensor issue too. I believe you're onto something with the CHT sensor. I had already tried switching out the IAC for a new one and nothing changed.

I recently had a misfire and checked the plugs to find they were covered in oil, cleaned up the mess and tightened my valve cover a bit. Fingers crossed that it will fix the problem, otherwise I'll put on new gaskets. I'm guessing my CHT sensor is oil soaked too and that may be causing it to misread. I'll take a look at it and clean it up to see if that fixes anything. Thanks again

 

Well I removed and cleaned up the CHT sensor and that didn't seem to change anything. IAC is new and that hasn't changed anything. Time to replace the OSS sensor...but I can't for the life of me find the replacement part. Its seems all of the ones that I am finding have the fastener on the wrong side. What's going on here? I included a picture of the sensor that i believe to be the oss sensor. 2011 ford ranger 2.3l manual.

 

Update: I believe this vehicle is outfitted with an electronic vehicle speed sensor and that is what is pictured. I unplugged it and the truck would die while coasting and I had no speedometer or odometer. Kind of thinking that is not the issue. I unplugged the CHT sensor and immediately noticed i had no temp gauge, drove around and not much changed with the idle. Considering replacing this, especially because the electronic speed sensors are 50 bucks and the CHT sensors are 20 :)

 

Ford calls it an OSS(output shaft speed) sensor on 2001 and up Rangers

Was called VSS(vehicle speed sensor) on 1997 and earlier

1998-2000 Ford used rear axle ABS sensor for "speed", and ABS

Not sure what you mean by "fastener is on the wrong side"?
The plastic sensor can be turned inside the metal hold down to any orientation you need for the connector

 

Replaced the CHT sensor, no changes, replaced the IAC valve with new Ford part, no changes. This is a video of what it looks like when I hit a stop, idle rises, then falls. Every time. Thoughts?

 

I was looking at the ones for automatic transmissions I suppose. I think I finally found the right part 4L5Z7H103AA - would you advise to replace this next? Seems like the logical next step.