Had partial loss of engine power above the airport. Noticed several trailers in the parking lot as I was circling down for an emergency landing. Saw there were drag racers on the runway on a Saturday afternoon. No NOTAM, which was confirmed by Denver Center. No answer on CTAF. Diverted to KCNP and fortunately made it.

Inspect the runway before committing to landing. Found a truck parked across the runway with no NOTAM, no runway closure signs at 11am on a Monday. Seem to be more concerned with their weekend drag races than with aircraft operations safety.