Some stress today when climbing out from KCRE at Myrtle Beach, which of course does not have a maintenance shop.  Savvy Breakdown Assistance is helping (this is a nice benefit of Global Insurance BTW), and I'm flying home commercial.   Here's the scenario: I am climbing out through ~2500ft and notice sudden roughness and see fluctuating RPM  (I initially think the governor is croaking).  I level off and reduce power to 2300 squared, but the roughness is no better, and rpm does not stabilize