Originally Posted by Jamieat

The misfire data by cylinder can be seen through the mode 6 data as the other post suggested.

In order for the "Misfire Monitoring" PID to be active, a 'drive cycle" must be completed.

The Misfire Monitoring requires you to do 3 times..........decel from 60+ mph down to 40- mph without touching the gas during the deceleration process.

This is part of the necessary data the parameter needs in order to complete its evaluation and all of the accessible data be displayed.

If you see a P1000 code, it simply means that all of the "drive cycle" requirements were not met in order for all Mode6 data to be complete and accurate.

It sounds crazy maybe, but, it is how the PCM operates its diagnostic procedure.


I've chased a intermittent / random misfire for a month now and this was how I found the problem cylinder as it might only misfire three or four times on a 30 min drive.

One thing to check in you trouble shooting which is what was causing my misfire.

Inside the plug/electrical connector or Male side of the connection, there are two Female holes. If you look behind them, there is a rubber gasket that seals the connection and prevents vibration as well. The gasket had came out of it's seat and was pushed up into the back of the plug and was preventing a proper "mating" of the connection causing the misfire.

Used a O Ring tool to fish it out and reseat it. I found two others that were not properly seated as well.

They seem to dry out over time so, I took the three I found with issues completely out, cleaned them off, reinstalled, and used a toothpick to apply a tiny amount of dielectric grease just on the rubber, to help the housing slide around it and not "drag" it from it's proper seat.

If you can identify the cylinder/s, then you can pursue other means of diagnosing the problem. I highly recommend getting the diagnostic data before throwing parts at it and hoping for a fix.

Good luck and keep us posted.

Originally Posted by Jamieat

Also,

did you torque the plugs on install?

If not, you need to do so. Spec is 23-27lbs. I did all of mine at 26.5.lbs.

These trucks are super picky about secondary ignition components and installation. The plugs have a tendency of coming loose and getting "blow by" of exhaust/unburnt fuel so, proper torque is imperative.

What brand and number plugs did you use? Motorcraft and Champion seem to be the two brands with the most sucess. SP546 is latest MC Updated version.

You should also do (very important) a reset of all adaptive learning parameters when doing any work/replacement of parts. This will allow the PCM to adjust the fuel trims, shift points ect for the new components. It will help idle and shifting parameters as well.

It goes unmentioned most times but, is an important step to ensure the PCM recognizes and compensates for the new components operation v/s the old and adjusts adaptive learning parameters accordingly.

It would eventually catch up and do the same thing, but, if it's been 10 years since a reset, it'd probably take about that long to catch up so, best to take 5 mins and reset it yourself and get results instantly.