Gilly,

Actually I do pressure wash my engine pretty regularly. Which got me to thinking. The spark plugs I removed were way tighter than they should have been. I wonder if all my engine washing may be to much of a good thing being bad. Maybe all that washing caused the plugs to corode enough to make them very tight.

Below is a photo two of the plugs I removed. Do they look like the ones you remove or do they seem to have more corrosion than they should?