So I've been trying to clear all my codes and get my 2004 Ranger Edge 3.0 v6 in better operating order but I'm about fed up with all this. I've had the truck for almost 4 years and have done maintenance and obviously fixed emergency situations but I'm financially ready now to be able to get my friend as closely back to the "showroom" as possible and the motor/front end is my opening act. So I spent all of last weekend trying to clear, what I'm now finding out is the famous P0112 code. Meaning I needed a new Intake Air Temp. Sensor. So the first thing I did was get a new one. Then I spent 3 days trying to find it on my engine. Well, it appears my engine is not equipped with this particular sensor. So I changed the Mass Airflow Sensor for good measure and had the codes cleared. about 5 min later the engine light came back on. Instead of freaking out I just went on as normal, since the light has been on the entire time I've owned the truck. The next day (yesterday) I stopped at my local parts store and had the codes read again to figure out why the engine light came back on. The tech said, "you don't have any hard codes". So I asked, "Do I have any codes, any at all, making the light come back on?" The answer is NO! So now the engine light is still on and there aren't any codes showing up. I should also telll you that when I start the truck, it revs up to almost three grand for, as little as 30 seconds to as much as 10 min. In addition, when I'm driving sometimes the idle will kick up and its hard to stop the truck at stop signs or if someone stops in front of me, which has proven to be somewhat dangerous. If I shift into Neutral it revs up to around 3,000 and then immediately drops back down where it should be. If anyone had any words of advice please feel free to message me and add info to this thread. Thanks for accepting me guys.

 

Im not sure this is causing your issue, but i had a issue with idle and this was my problem. My Idle Air Control Valve was very dirty. I cleaned it and it fixed my problem. Yours may be bad. What it does is allow air to bypass the throttle body for warm up and should shut after 30 seconds to 1 minute. Now mine kicks down after 1 minute full cold and 30 seconds after every start thereafter. It's worth checking on your. I'm attaching what your looking for. Hope this helps.
as far as the code, there is permanent witch can only be cleared by a good code reader or dealership. Why the light stays on is probably due to the permanent code.

 

this is what your truck calls for, not for my jeep lol.