Thank you all for information that helped solve this problem. About a month ago, my f150 started stumbling/misfiring. It had also set a P0402 code (high EGR flow). This turned out to be the DPFE sensor. I was originally worried that the EGR ports were clogged and this was contributing to the misfire. Determined that the EGR ports were clear since the misfire was occuring at light loads. The EGR opens at cruise and light loads leaning out the mixture and making it hard to ignite. It finally got bad enough to set P0302 so replaced coil and spark plug. It is now running much better. I suspect that this coil was weak from day one since at idle it would bounce between 500 to 600 rpm and is now real stable at 600 rpm.


Note : it had to get really bad to set off misfire code.

'01 Supercrew 60K miles.

 

Good for you. You just showed how good the missfire detection is and the results of poor spark plugs during just the cruise routine.
Gas or additives will contribute to early plug failure if the additive results in any deposits on the plugs.

 

i got the same symptoms but mine stumbles after putting in gear and mashing the break. But only so often. My DPFE sensor was changed about a year ago(recall), but it idles around 5-6 thougsand RPM's as well. Would you recommend changing my coil and spark plug? No codes but like you said maybe it isnt bad enough yet>