[FIXED] 08 Town&Country 3.3L- Intermittent Misfire w/ Intermittent running Comp

Hello, I just purchased a 08 Town & Country Van with the 3.3L Engine,

It has a Misfire in Cylinder 4 which is causing a CEL which means I will fail emissions. I can hear the cylinder alternating between misfiring and firing in the exhaust at idle. the rpm drop then pick back up (the rpm gauge is fluctuating.) up-down-up down every 3 or 4 power strokes. When the plug wire is disconnected, its a constant misfire.

Today I tried a running compression test.

The gauge seems to be showing intermittent compression. Some times it jumps, sometimes it dosent jump. Raising the rpms just makes it alternate faster. just like the misfire.

Would a bad ring cause this?

Other things Ive tried before today:
Scanner readings:
www.dropbox.com/sh/28oh8vgmb6eezav/AAAV5...8vk-IjEDarR_BQa?dl=0
All codes have been extinguished except Cylinder 4 misfire.

New plug - can see spark in spark tester
New ignition coil - no difference
swapped wires with another cylinder - no difference
Leak down tester - at 100PSI barely any leakdown, stays at edge of "set" area.
compression test while cranking 165. All others about the same.
Replaced head gasket - no difference
Tested vacuum - 19Hg at idle, lowers to 18 during misfires.
Disconnected and covered EGR port on intake - no difference.
Disconnected and covered PVC valve input on intake - no difference.
Exhaust backpressure in upstream exhaust is almost 0.
replaced intake and exhaust valve spring - no difference, rockers are moving up and down.
swapped injector - no difference, can hear clicking with screwdriver test.
Tried adding a bottle of Techron to gas tank, drove 15 miles - no difference.
Test light on injector plug shows pulsing injector signal.

Can't test fuel pressure because theres no shrader valve.

Thanks for posting that video! Definitely an issue there... It would seem to me that the needle jumps would indicate good compression, and the lack of jumps indicates the issue, right? For science, have you tried doing the same test to another cylinder? Just to make certain that the gauge is working correctly, and to have a known good cylinder to compare to.

When you replaced the head gasket, did the head have any valve work done? I ask because there's only a few things I can think of that'd cause this. One would be a sticking valve in its guide. Another would be a failing lifter. Last, but probably least likely is a worn cam lobe. Least likely because I believe a worn lobe would be more consistent than this.

Yes, figured the video would help describe what im seeing. I tried it on another cylinder and the compression gauge bounces consistently, not intermittently. No head work was done. I should have replaced the lifters when I had the head off. I just bought some lifters so i will pull the head again today and report back after replacing the lifters. Thanks

Let us know how it goes! While you've got the head off, absolutely have a good look at the lifters and cam lobes. Maybe consider sending the head to a machine shop?

I replaced the lifters and drove it 14 miles so far, no DTCs. So it was faulty lifters, Thanks.

Nice! Very nice to hear this one ended up fixed.

Again, sweet video of the running compression. Really cool to see the needle behavior with the faulty lifter.