Originally Posted by dannyzabolotny

My 4.6is developed an occasional rough bump while idling over the weekend... it felt like a little nudge from under the car. After a bit of scanning with INPA and using the smoothness graph, I determined that cylinder 7 was running a little rough but not enough to trigger a misfire or a code, so I swapped in a brand new Bremi ignition coil to replace the original 2002 coil. That seems to have solved the issue, and the smoothness graph in INPA showed a big improvement. I'm sure if I hadn't done anything it would have developed into a proper misfire with codes, but I'm happy to have taken care of this before it became an issue. Especially since it's going to be 120º on Tuesday... I don't want to deal with anything when it's that hot.