My car has always ran strong but recently I noticed some hesitation, probably clutch mostly , none-the-less I wanted to check compression, since ignition system seemed fine. I'll share the results in hope anyone wishes to give their take on it.I'll save spark plug condition for last.
In order-210psi, 205psi, 165psi, 198psi.

Compression shouldn't be more than 20% difference between any two readings, so cylinder 3 has me worried. Comparing #3 and #4 that puts the difference right around 20%. I didn't compare #3 to the others for reasons I'll share later. Only two issues that I can remember would be the cause of the indicter, poor piston-ring seal, or poor valve seat seal(due to carbon deposits). Both are very likely on 160,000mile engine. And, like a dumba** I forgot to perform the tried and true three teaspoon oil trick for #3.

Number #1 and #2 have unusually high compression when compared to the #4 as a baseline, and Haynes manual standard of 192psi. Here's the fun part, while removing spark plugs I noticed a good amount of oil on it, yeeehawww. The plugs were completely covered, so I assume, since the top of the plug was covered, oil is leaking from the spark plug wall cover around the gasket area, it was too dark to confirm this. I recently had a timing belt/water pump change at the local shop, so I ASSume they didn't use ATV(or as I say goop) completely around the gasket. I imagine oil was probably pooled in the spark plug well, I was to busy BSing with buddies, and the little amount of oil drained into the chamber, thus given unusaully high compression for these two cylinders?

More fun, after the compression test I noticed a loose PCV valve. I removed it did the shake test in seemed OK, and reinstalled it. Didn't do a vacuum test. I'm not to fimiliar with the PCV system, so I have a question. After checking the spark plugs I noticed #4 cylinder is running lean. I know under high vacuum conditions the PCV valve allows excessive blow-by. Would a loose or bad PCV valve cause a lean condition? What's unusual, the PCV valve is located exactly between #1 and #2 intake runners, does the location make a difference which cylinder will run lean?

I'll have to perform another test, and leak-down test. But, any input will be appreciated.

BTW my oil is very clean, after 3500 miles.

 

ttt

 

You're supposed to compare ur lowest to the highest on ur compression test. Evidently there is something definitely wrong due to ur range of variation from 210 to 165psi. It can mean many things including worn rings, leaking valves, head gasket blown, or cracked head. Get that leakdown test done as u planned and post the leakage results.

 

I'd deal with the other issues first, like the sparkplug tube seals and the PCV valve; that's easy stuff. With the sparkplug tubes dried out, run the car some to burn off the oil you got in there. Then do the compression test again. Sounds like there's enough question about your compression test that you can't trust those numbers.