C208B Rudder Issues

I was flying the Carenado Cessna 208B Super Cargomaster in FSX today when I had some rudder problems and had to return to the airport. This problem was occurring before but on a very small, negligible scale. It was only today that it became a problem. What happened was my rudder kept deflecting all the way to the left (captain's side) of the aircraft. I searched multiple different dials and switches and ended up checking everything in the VC and couldn't find the cause of the problem. My rudder trim was set to exactly 0, I was not imputing any rudder actions on my T Flight Hotas X, the pedals in the VC didn't appear to move with the rudder, but still every minute or so my rudder would go all the way left and then recenter after the autopilot corrected it. Another unusual thing that happened on this same flight is that I was not able to go above 140 knots for some reason. Normally, the C208B cruises at around 160-170 knots but I could not get it to go more than 140 even with full power, full prop control, full mixture, flaps up, inertial separator off, and at level flight. Unlike my rudder problems, this airspeed issue did not occur at all before this flight. Can someone tell me what's going on here? I tried to reproduce the issue on other aircraft and it just seems to be on the Carenado C208B.