My 3.7 used to tick. started a few months back. it was so gradual that i didn't notice it. after a while it developed an intermittent misfire. In reading the code it was a misfire on cylinder 5. we found a cracked plug, which explained the misfire, or so i thought. We also moved the coil from cyl 5 to cyl 3 at the same time. This was done to help trace it if it returned. The tick was gone for about a week, then the misfire came back about 2 weeks after that. When reading it, the misfire moved to cyl 3, so i replaced the coil. now the engine is quiet, and has more power then before replacing the coil.
The coils on the 3.7 runs 2 plugs, So I only have 3 coils in the whole truck. On a 4.7, each coil also handles 2 plugs, but there are 8, as there are 2 plugs per cylinder. Even though one part of the coil is failing, because there are 2 plugs, one fires before and one after TDC, the engine might not detect a misfire, even though you can hear it. In my case, the bottom of the coil failed causing the misfire only on one cylinder.
in my truck, I noticed that it didn't seem to have as much power since about mid summer. When i cleaned my K&N drop in about 2 months ago, it seemed to help, but it was not like it was before. The coil made all the difference in my case. Not that there is a lot of horsepower in the 3.7, but my K&N, my E3 plugs and the 3.92 gears make this truck perform pretty well. I used be able to do standing wheel spins including smoking one tire before (no LSD or locker in the rear) but i don't do it with my new tires, too much traction on the General Grabber AT2's. Now that there is snow and ice on the roads (I live in Northern Ontario, where it was -24 C yesterday) I'm able to spin 3 tires with ease in 4WD. I can't wait to be able to put in an LSD in the rear end.