Well, we had a third coil pack die late last night on my wife's 2017 Limited while still about 30 miles from home.
It started out subtly, while we were on the interstate. The ride felt a bit bumpy at times, and at first I thought there was some kind of surface issue with the pavement in the area. But then I noticed that the "bumpiness" only occurred when I was pressing the accelerator. As we got closer to home, the roughness under acceleration became more pronounced and the check engine light started flashing intermittently and sometimes there would be an audible warning ding.
When we got home, I hooked up my OBD-II scanner dongle and pulled the codes. It showed code P0306, a misfire on cylinder 6,
It looked like I was finally out of luck since cylinder 6 is one of the cylinders hidden under the intake manifold. My two prior ignition pack failures were on cylinders 1 and then 5, which are accessible without removing the intake. Replacing those ignition packs only takes a few minutes, but removing the intake to reach the other cylinders is a bit of an ordeal.
I kind of knew this day was coming, since the two earlier failures had been within a short time of each other (somewhere in the 70,000 mile range). At over 90,000 miles I figured I was running on borrowed time, so I already had four new ignition coil packs on hand, as well as four new iridium spark plugs (I already replaced the spark plugs on cylinders 1 and 5 when I replaced the packs).
Unfortunately the timing was not ideal, since my wife was starting a new job in the morning. I started at around 11:30 last night, and finished up around 4:00 this morning. Not counting test driving the van and putting my tools away, the job probably took 3.5 to 4 hours, including time spent watching YouTube videos for reference, lol. I used the two videos I linked earlier in the thread. Here it is with the manifold off:
The YouTube videos definitely helped, but they glossed over some of the parts I found trickier as an amateur mechanic, such as how to unlock and disconnect the various electrical connectors without breaking them.
Everything went pretty smoothly, except that when I thought I had removed and unbolted everything, I still couldn't pull the manifold completely off because it was hung up somewhere down and on the right. It seemed like there was still a bolt attached, but I couldn't find it. I finally found the following illustration, which showed me the bolt I had missed. It's the bolt labeled "2". It's pretty much impossible to see hidden behind the two big electrical plugs down on the bottom right side of the engine.
Here's the thread where I found that diagram, which has other useful information for the process:
Where exactly are the spark plugs located on our pacificas? I replaced the air filter yesterday and was kinda looking around for them i didnt see much. 3 might be located back by the firewall? I am afraid someone is going to tell me under the intake and that does not look fun to take off. I am...
And here's how my spark plugs looked after 90,000 miles:
I replaced the original Champion Iridium RER8ZWYCB4 plugs with Denso SXU22HCR11S 3461 iridium plugs.
Yeah, it was a bit of a pain doing the repair myself, but I think that anybody who is decently mechanically apt should be able to do it. If I had to do it again it would go much quicker. I imagine a real mechanic would be able to complete the job in under two hours. But I feel good about saving several hundred dollars, and being able to get my wife's van fixed overnight instead of waiting for a repair shop to fit it in.