Withthe plugs out, "When in gear it takes quite a bit more force," is NOT what I would expect. It looks like something is "putting on the
Re-reading....is that silver on the plug aluminum or steel deposits? If so....uuurrrrfffff.
Sounds like a blown head gasket to me. Clean plug, low compression.
Relative easy fix.
Only way to know for sure is to pull the head.
We were out on Lake Michigan for a cruise and on the way back, I started to get an audio alarm (2 beeps) every 5 minutes. Checked all gauges (twin 5.0L
Doesn't make a difference