what RPM's is it running in? The Hybrids engine is a natural atkinson cycle motor so it doesn't make as much punch as something forced. Hauling all the extra hybrid heft up those steeper grades will certainly have it screaming for mercy...
Monitor the situation but unfortunately I don't think there is any legitimate solution besides avoiding overly steep grades
(of course that's not a viable suggestion either)
Monitor the situation but unfortunately I don't think there is any legitimate solution besides avoiding overly steep grades