Just a suggestion here, but maybe you should take the time to determine just what is off kilter. At 50 LOP you are right on the edge of a significant reduction in power. I would suggest leaning beyond the 40 LOP mention until the engine loses significant power. It shouldn't take much. That is proof positive that you as lean as the EGT says you are. Given that confirmation, the anomaly must be an error in the fuel pressure reading, or some problem with the fuel system that allows normal mixture to be maintained with an abnormal fuel pressure reading. The engine tells the tale - it can't be fooled.
Just a thought from one not too familiar with the Continental fuel system.
Gary Casey
Just started having a change in fuel pressure at cruise. I have a Legacy ... 550N ... been cruising 40 to 60 degrees lean of peak with no problem, with fuel pressure above 8.2 psi. Depending on altitude 2500 rpm - 2300 rpm ... 11.5 to 11.8 gph ...
The last few flights I can not get 40 degrees lean of peak at any altitude without the fuel pressure dropping below 8.0 psi ... even if I turn on the fuel pump to low = 9, 500 - 11,500 - 12,500 ????
any ideas on what is going on???? Takeoff fuel pressure is 28.0 psi ....
Thanks ...
Alan Crawford