Bellanca viking pilot reported that a rough running engine resulted in a precautionary landing.

Attributes
ACN	1740951
Time
Date	202004
Local Time Of Day	1201-1800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Viking
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Engine Exhaust System
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 11 Flight Crew Total 1325 Flight Crew Type 1115
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

While I was at 5;500 ft. In cruise I heard a loud bang and the engine started to run rough. I immediately turned off the autopilot and contacted approach and told them I had engine problems and I needed [priority handling]. They informed me that I had one [airport] to the south 3 miles; one to the north 5 miles and one to the east at 15 miles.I immediately turned to the south and proceeded to configure the plane for best glide and pulled the throttle back to idle.I set up a base leg to [the] runway with gear and flaps up. Once I was on final I dropped the gear and lowered flaps to half. I was a little high on short final and applied full flaps. I touched down right on the numbers and was able to taxi to parking.we immediately called FSS and told them we were safe on the ground and to please relay that to approach.when the fire department arrived I informed them that everything was okay and it was just a broken muffler that caused the landing.

Original NASA ASRS Text

Title: Bellanca Viking pilot reported that a rough running engine resulted in a precautionary landing.

Narrative: While I was at 5;500 ft. in cruise I heard a loud bang and the engine started to run rough. I immediately turned off the autopilot and contacted Approach and told them I had engine problems and I needed [priority handling]. They informed me that I had one [airport] to the south 3 miles; one to the north 5 miles and one to the east at 15 miles.I immediately turned to the south and proceeded to configure the plane for best glide and pulled the throttle back to idle.I set up a base leg to [the] runway with gear and flaps up. Once I was on final I dropped the gear and lowered flaps to half. I was a little high on short final and applied full flaps. I touched down right on the numbers and was able to taxi to parking.We immediately called FSS and told them we were safe on the ground and to please relay that to Approach.When the fire department arrived I informed them that everything was okay and it was just a broken muffler that caused the landing.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.