C172 pilot reported engine roughness and a loss of rpms led to a diversion.

Attributes
ACN	1604801
Time
Date	201812
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Component
Aircraft Component	Engine
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 8 Flight Crew Total 65 Flight Crew Type 65
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

At 4;500 feet; the engine had a sudden loss of RPM and subsequent roughness. Carb heat was applied and mixture was set to full rich; was unsuccessful at troubleshooting. The engine continued to run rough and I made a 180 degree turn to head to ZZZ airport to land. Advised ATC and landed safely.

Original NASA ASRS Text

Title: C172 pilot reported engine roughness and a loss of RPMs led to a diversion.

Narrative: At 4;500 feet; the engine had a sudden loss of RPM and subsequent roughness. Carb heat was applied and mixture was set to full rich; was unsuccessful at troubleshooting. The engine continued to run rough and I made a 180 degree turn to head to ZZZ airport to land. Advised ATC and landed safely.

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.