Did you ever get rid of the code? I had the same code on my 2.3 about 2 weeks ago before I did a 2.5 swap. Right after the swap I had the same code come on with the same problem........different camshaft AND crankshaft sensors too! I ended up reading a possible cause could be faulty alternator diodes transmitting stray current through the wiring and interrupting the sensor.
I swapped out alternators and the misfiring was gone...........but only during driving. It was still there at idle a little.
I ended up ripping out my entire wiring harness and found a couple frayed wires. I also replaced both wires "starter to battery" AND "alternator to switch" with brand new 4 gauge battery terminals. I wanted this problem gone!!!! I also replaced the plug, wires, and fuel injectors off of the 2.5 engine. I've replaced relays as well.
After all of this, I noticed a little rattle under the Rnager so I crawled under it and determined that my catalytic converter was bad too. Can I get a break here guys? I went to my exhaust guy and sure enough I had a bad partially clogged cat. I had both the cat and muffler changed out and since then the Ranger has been running top notch. The light has stayed off as well so far.
Sorry for such a long post, but it appears this problem is a code thrown by the PCM when it cannot acurately determine the exact cause of the problem. I also came to the conclusion that this could also be a PCM problem itself but I don't have access to a "known good" PCM right now. It seems as though I have licked it for now but the IAC valve still does not increase engine rpm's when the air conditioning is engaged causing a rattle in my throwout bearing.
Other then the "iac" problem, my Ranger is running GREAT once again. I need to go now though so I can replace the old pilot bearing I used on the 2.5 motor which is causing hard shifting into 2nd and 4th. I'm an idiot cause I know better and had one in my toolbox anyways....hahaha. PLEEEAASSE, let me know what you find out because I'm sure this code is driving people mad and maybe we can help. Take care bro.