also check for a the return air path , you may have some restriction on that side. On our RL38 the return vents are in the stairs risers. Check for Bees making a nest in the tube , this isn't all that uncommon if its parked for any length of time in one spot.
Mark & Melissa
2015 Redwood RL38 , Kodiak disk brakes , 17.5" tires , 8K Morryde IS