Have tuned engines with coatings one both pistons and chambers along with ex port. If you get a false signal its only going to show up on the data log, if you can hear it well then you have other issues. As far as valves not sealing a coating really would not create that. Even if it was extremely think at one point the valve would go through it like butter. Its not a anti wear coating( say .0015-.002) its very thin, on a area like a valve and seat the contact point would clean itself in extremely short order. Like a few raps with a rubber mallet or your palm. Those guys are very sharp, Mike will tell you what is going on and how what he needs to correct the issue.