Low Fuel Pressure

If its not your sensor or poor electrical connection in the circuit it is probably a phenoenom in the fuel ciruit that some Rotax 912 powered aircraft have experienced intermittently. This topic has been discussed many times on this forum but the root cause of this has never been exactly stated. My Remos GX has had this same issue intermittently in its 10 years of use and has never lost power nor have I ever heard of any one else loosing power with these symtoms in regards to fuel fluctuating pressure. Check out this excellent article from Rainbow Aviation on the Rotax 912 mechanical fuel pump.

https://electricmotorglider.com/2018/09/21/fuel_pump_912/

Thank you Garrett!  I'll gladly read the article and happy to know that somebody hasn't lost power...that does jump to the forefront of my mind when I hear "fuel pressure" climbing out.  

You are probably seeing Vapor forming and clearing in the hoses.
With low wing tanks, the Vapor naturally want to flow uphill and quickly enters the carb bowls and is vented away.
You may have a restriction on the suction side of the pumps causing low pressure fuel cavitation at high flow / power settings.
I would inspect your fuel filters to see if they are the source of the problem.
Check for a kinked Fuel line while you are at it.

Fuel Flow is all that is important.
We use fuel pressure as an indication of potential fuel flow because the sensors are 4x less expensive and much less problematic.
Price a Fuel Pressure Sender  vs. a Fuel Flow Transducer  to see the difference.
As long as the flow exceeds the consumption, the engine will power on.

Thank you Bill, I'll have my mechanic check it out.