1994 Chevy Astro Hotter the engine, the more it doesn't wan

. But it does turn over EVERYTIME!

Have had battery, starter, and alternator checked out when engine is hot (after driving the 30 minutes to town) and manifesting difficulty turning over, but all the listed components checked out to be preforming excellently.

Someone along the line said he heard of something called "compression buildup" (I believe that was the expression used) can happen where excess compression is just making the engine harder to turn over, and would account for the difficulty in turning over although the alt, bat, and starter test out o.K?

Can anyone confirm this "compression buildup, " what causes it, and what the fix is?

Thank you.