How far gone does a COP have to be to show up on a code reader? 2000 F-150 4x4 5.4L starting to misfire but not showing up on OBD II PocketScan.

 

Not sure about a COP, but FWIW, I had a spark plug (Bosch) go bad after about 20,000 miles.

The motor ran really bad for at least a month before it would throw a code. I spent alot of time trying to figure out the problem. Scanned the codes a few times just to see if ANYTHING would come up.

Eventually, it finally threw a code (for a cylinder #6 misfire) and I replaced the plug and had the truck fixed within minutes. I could not believe the motor could run so poorly for so long without throwing a code. Would have saved alot of time and frustration if it generated codes easier. In my case, I knew it was running like it had a bad plug, but since they were relatively new, I figured it was something else.

 

Thanks DBD. Truck finally gave up the code. Should have her fixed up momentarily.

 

Anybody know where to find a map of the cylinder configuration? I'm on the road and don't have my shop manual. I need to know which cylinder is the #1.
Thanks.

 

4 8
3 7
2 6
1 5

Front facing down - #1 is the first one on the passenger side.