So back to your readings.
14.7psi is normal air pressure or 1 atmosphere/bar. You were measuring nothing elevated at idle.
At 2500 revs, you got 15.4psi. So the simple math here is 0.6psi. So far, I'm not seeing any clogged coverts.
Do the same at 4000-5000rpm. If you get 30psi then..........