A C182 lost power at 9;000 ft in cruise; then began running rough so the pilot declared an emergency...

Narrative:

While in cruise flight at 9;000 ft. MSL manifold pressure dropped. I made adjustments to mixture and power settings which temporally restored power; but not to full power. A few minutes went by; and I looked at the egt gauge and noticed that the number 1 cylinder dropped off and all of the sudden the engine and plane started vibrating; as if the cylinder blew. At that point I communicated with center the nature of my problem and they asked if I wanted to declare an emergency; and I replied 'roger; I am declaring an emergency.' I was given clearance to descend at pilot's discretion and received vectors to a nearby airport. As I started my descent; the plane was regaining power and the vibration stopped. I was advised by center that there were closer air fields; however I had no weather information as to ceiling heights or conditions on the ground; so I chose to continue to the divert airport as the plane seemed to regain its power. I was told to maintain 2;000 ft and as I arrived at the airport environment I was told that I could change to the tower frequency. I broke out of the cloud deck at 1;100 ft MSL and was parallel to runway xx in which I continued downwind and turned left base for a short final to runway xx. I was able to make a normal landing and taxi to the FBO for repairs. Fuel remaining upon landing was 3.5 hours.

Original NASA ASRS Text

Title: A C182 lost power at 9;000 FT in cruise; then began running rough so the pilot declared an emergency when Number 1 EGT was seen low and diverted to a nearby airport. The engine seemed to recover somewhat during descent.

Narrative: While in cruise flight at 9;000 FT. MSL Manifold pressure dropped. I made adjustments to mixture and power settings which temporally restored power; but not to full power. A few minutes went by; and I looked at the EGT gauge and noticed that the Number 1 cylinder dropped off and all of the sudden the engine and plane started vibrating; as if the cylinder blew. At that point I communicated with Center the nature of my problem and they asked if I wanted to declare an emergency; and I replied 'roger; I am declaring an emergency.' I was given clearance to descend at pilot's discretion and received vectors to a nearby airport. As I started my descent; the plane was regaining power and the vibration stopped. I was advised by Center that there were closer air fields; however I had no weather information as to ceiling heights or conditions on the ground; so I chose to continue to the divert airport as the plane seemed to regain its power. I was told to maintain 2;000 FT and as I arrived at the airport environment I was told that I could change to the Tower frequency. I broke out of the cloud deck at 1;100 FT MSL and was parallel to Runway XX in which I continued downwind and turned left base for a short final to Runway XX. I was able to make a normal landing and taxi to the FBO for repairs. Fuel remaining upon landing was 3.5 hours.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1059586
Time
Date	201301
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Make Model Name	Skylane 182/RG Turbo Skylane/RG
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Cylinder
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Private Flight Crew Instrument
Experience	Flight Crew Last 90 Days 20.3 Flight Crew Total 656.3 Flight Crew Type 536.3
Events
Anomaly	Aircraft Equipment Problem Critical Inflight Event / Encounter Weather / Turbulence

A C182 lost power at 9;000 ft in cruise; then began running rough so the pilot declared an emergency when number 1 egt was seen low and diverted to a nearby airport. The engine seemed to recover somewhat during descent.