Rough idle

Did compression check today and #1 cyl was 0, all others were between 155 and 175 psi after 6 strokes(first stroke was above 130 on all but #1). Looks like either a valve is stuck open or a valve spring broke. Customer deciding what he wants to do now

I used a small LED snake light to look in through the plug opening and all I could see was the piston, of course don't get to see much that way. Plus with the research I have been doing this model Jeep with the 3.7 has a sludge problem and valves like to stick open. Also some cases of broken valve springs.

Engine Performance problem
2006 Jeep Liberty 6 cyl Four Wheel Drive Automatic 50000k miles

po300 code engine misfires rough idle at times new plugs didn, t help what next?