P1309 What could it be
I had a check engine light (CEL) p1309 came on on my '99 Ford Ranger 4.0L. My OBD II indicated the code to be "Misfire Monitor Disabled". Because I also heard periodic chirping noise along the engine compartment firewall and fact that occasionally the engine seem to misfire, I suspected that I was having a camshaft synchro problem. I took it to the mechanic and they replaced the camshaft synchronizer. The old one had bad bearings. That corrected the problem, chirping noise gone, and the vehicle idled smooth and run well on the freeway. BUT, the CEL came back on again although the vehicle seemed to be running well. With the exception of the annoying CEL light on, one wouldn't detect anything wrong with the vehicle. So what can it be? Any ideas? Could it be a PCM problem but if is wuldn't that affect the performance of the engine?