98 Voyager 3.0L engine light again

[Amechanic]

Hi all, I followed your suguestions to replace spark plugs, spark plug wires, and ignition coil. The engine light is still on for cylinder #6 (it will go away for about 200mi after I disconnect battery cable for a while and the light will be on again). Yesterday, I sent the van to a dealer here. They just called me telling me the pressure for cylinder #6 is low. It will cost $700 for just further looking at the issue.

Any suggestions/comments on fixing the low pressure by myself? Thanks in advance

[RIP]

If by low pressure they mean low compression, any way you look at it, it's a fair sum of money to fix. Anything that would break a tight seal in the cyclinder during the compression stroke is suspect. That means valve seats, valves, rings, scored cyclinder walls, head gaskets, or worst of all a cracked head or engine block. I haven't had any experience with the inside of an engine so I can only guess at the best way to narrow those down. I'm sure somebody can chime in and give you more details.