Lower Rpm’s

hello, recently my 912 with 1100 hrs started producing lower RPMs , static during run up and climb out.

normal rpm with ( un touched prop setting ) would be 5250 run up ,5000-5200 climb out, and 5300-5450 cruise 

not sure if it’s because of the warm humid Missouri temperatures, i’m sure it plays a factor however I’m leaning towards a fuel issue as during cruise fuel pressure warning light comes on and it drops to about I think the warning light is set for 2.5 psi, to rectify I’ll put on the electric boost pump, however I don’t have to run with it in definitely once I get out to say 4500-5500 feet it’s fine and RPM seems to progressively increase, I have had the plane (TL-stingsport ). four years and I’ve never messed with the carburetors or floats and I’ve never changed the mechanical fuel pump, Air filter and plugs get changed annually ( 100 hrs per year) . I’ve never had an issue with the filter or too much oil on the filter, my last annual just about a month ago I cleaned and oiled air filter and new plugs so they’re relatively new! All else checked out ok, compressions, gearbox torque ck, however I have noticed very small particles in my fuel filter black and a very small amount of oil is coming out of my cowling hard to track down the leak it’s not very much in one it’s very minor, anyway want to check to see if anybody in the group has ever had issues with the RPM drop. Hey suspecting air fuel mixture would be my first reaction, with the humid hot air I’m thinking running rich but at the same time with the low RPM I would almost assume it’s not getting enough fuel so I’m thinking carburetor rebuild any ideas would be appreciate it safe flying and blue skies.

stingsport.