This pertains to my 04 Aviator... So for about the past year every 6-8 weeks Cylinder 6 would miss once then never do it again. Mechanic A confirmed what I was thinking and said the coil was most likely dying and that as long as it's not doing it very often to just leave it till it worsens. Cut to the end of September and I'm getting ready to take a 6hr each way trip to Penn State to go to a football game so I figure let's just change it out now and not worry about it. So I have Mechanic B (who has done tons of great work for me over the last 5 years) swing by and swap out the Cylinder 6 coil and plug (even though the plug was only a year old). This is where it all starts going downhill. We start getting misfire codes for Cylinder 6 at a rate far far far worse than previously. So we get back from Pennsylvania and I take it to Mechanic A to look at since I can just drop the truck off and pick it up after I get out of work (I commute via train and Mechanic A's shop is right in the parking lot for the train station by my dad). He see's the misfire, cleans the MAF, cleans the TB, resets the fuel map, drives it around and it improves a lot. Still not a 100% smooth but honestly at 145K miles it's smooth enough and he said there was nothing of concern on his Live-OBDII while he was driving it. So I drive it around for about a month and a half with no issues; no misses, no CELs, no nothing. So last week we take it 3hrs to the Poconos for Thanksgiving. Drives great the 160mi there and drives great the 160mi back; no misses, no CEL, nothing. So about 4hrs after I get home I go out and run some errands and grab some dinner aaaaaand then it starts missing and throwing a CEL For misfire detected on startup and cylinder 6 misfire. ffffuuuuuuuuuuuuuuuuuuu.... But the thing is, it only does it when idle, and if it starts missing and the CEL starts flashing, if i start driving and give it throttle it just clears up. And I can be sitting at a light and it can be idling perfectly and then BAM it starts missing. But I never have any misses when I'm driving or on the highway cruising, but if I stop at a light it's like a coin flip if it's gonna start missing. Could this just be something like a clogged fuel filter or a weak/clogged injector? I don't think it's something catastrophic since it only started happening after I had the coil changed, and about 2 weeks before it was changed I drove to south jersey and Philadelphia with no issues. P.S. I hate cars....but I love them....but I reaaaaalllly hate them.