While flying this weekend we noticed again that our manifold pressure readings are wrong, going from 16″ at full power to 8″ at idle. They ought to be several inches of mercury higher at both settings. This is problematic because this same line provides the MP sensor on our electronic ignition, which will advance the timing at low MP settings, but since the engine is actually at high power and high RPM at take-off with this erroneous pressure reading, it risks moving the cylinder burn towards damaging detonation.