2012 22 MXZ with Indmar 6.0L has low MAP sensor reading

[WY22MXZ]

I was out on the lake and noticed I couldn't achieve full power.  When skiing I couldn't reach 30MPH and while surfing I couldn't get over about 9 MPH.  The same problem happened last year but then went away.  The boat ran good for most of this year and then this last trip out it did it again.  I was having problems with the O2 sensors but sense replaced them and no current error codes.  The boat does nto show any codes at this time.

I have a 2012 22MXZ and the MAP sensor is reading low.  Around 9 inHG.  I checked the manifold pressure with a gauge and it is right where it should be at 15 inHg.  I replaced the MAP sensor and had the same reading so I put the original back in.  The Pedal position sensor 1 voltage and Pedal position 2 voltage read the same at idle.  Around 0.80 VDC.  I'm told these should ad up to 5 volts like the throttle sensor does.  I disconnected the transmission temp sensor and jumpered the contacts and no change.  I disconnected the depth gauge and the paddle wheel and no change.  I disconnected the throttle and did get an error code but no change on the MAP sensor reading.

Any thoughts?

[justgary]

Your MAP sensor should read atmospheric pressure (~14.7 PSI, ~29.92 inHg, or ~1013mB) with the key on and engine off.  A bit less with altitude higher than sea level.  The MAP pressure will always be lower than that with the engine running, except maybe at WOT.  It should read the lowest at idle.