Hello Gents,
I have a 2005 Ranger 2wheel 3.0 that was an Indiana State Forest vehicle. It high idles at start up then drops back to normal after about 2 minutes. Less when warm. Big issue is that if you punch it, or many times, when you push it into high acceleration, it will get stuck at about 1500-2000 rpm. Feels just like cruise control however I don't have that option. Any help would be greatly appreciated.

 

First stop would be the TPS(throttle position sensor)

Get a volt meter and a sewing pin, straight pin.

Set volt meter to DC volts, like 20vDC setting

Remove throttle linkage cover, plastic piece covering linkage
Turn on the key, leave engine off.

There are 3 wires on the TPS sensor
Pierce the top wire with sewing pin
On the volt meter put the Black probe on a ground, battery is fine or clean engine metal part.
Put Red probe on the Pin
Should red 5.0 volts, 4.8-5.0 is fine, this is voltage From the computer
remove pin and pierce middle wire
Touch red probe to it, should read, .70-.99 volts, under 1volt
Slowing open throttle and watch voltage, it should increase slowly, no jumping around, nice and steady.
When throttle is open all the way it should be above 4.6volts
Then close, and watch voltage again.

ANY jumping around of voltage means replace TPS

 

Hey Ron and fellow Ranger owners,
Thanks for the tip. I replaced the TPS, problem not resolved. I have learned some more about the symptom and when it happens. The problem is much more prevalent when the engine is under a slightly heavier load like when the AC is on. Today I had the defroster on due to rain and whenever I pushed the rpms past around 2.8 to 3,000 rpms, the idle would stick. It stays there until I apply the breaks. It will continue to push the rpms until I get engine brake to below 11,000 or so rpms then jump down to like 5000 rpms. However, today I actually had to shut off the engine at one point to get the idle back down. Big problem getting worse. Any ideas would be much appreciated. Thank you!

 

Well, you needed to test the TPS not replace it, point being the voltage from and to the computer may have pointed to a problem, and not a TPS problem.

Just an FYI, 90% of all sensors or controls replaced by DIYers were working just fine.
40% of all sensors or controls replace by Professional mechanics were working fine, although some of these were replaced to pad the bill, lol.

So always test.

I would now check the throttle cable and linkage, could be a mechanical issue.
Remove throttle cover and open throttle all the way, remove cable.
Pull it in and out, see if it is smooth no rough spots.
Open throttle and make sure spring is tight, slide throttle sideways and make sure there is no side to side play that could cause it to stick.
remove "air tube" from intake and check if throttle plate inside is loose.