PA28 pilot reported radio malfunction along with gradual loss of engine power.

Attributes
ACN	1590273
Time
Date	201810
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Component
Aircraft Component	Air/Ground Communication
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 35 Flight Crew Total 225 Flight Crew Type 225
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Speed All Types

Narrative:

Problems starting aircraft. Attempted 3-4 times; then consulted [maintenance]. Tried a couple more times; airplane started with a loud backfire. Lost comm 1 at run up. Consulted [maintenance] again; just switched over to comm 2; finished my run up; and before takeoff checklists and took off. Got established and at 4500 feet cruising and leveled off and trimmed. Flight was beautiful until I noticed my airspeed started to fall. I was level and hadn't adjusted anything. I increased my power and it slowly kept falling. I leveled off again and it kept falling. I double checked my pitot heat. I pushed the nose forward to trying to increase my speed. It seemed to hold the airspeed; but as soon as I leveled off again it began to fall. During all of this; comm 2 went in and out. Center informed me ZZZ was right in front of me. I descended and landed without issue to myself or aircraft. Taxied off runway. I don't know what caused the issue.

Original NASA ASRS Text

Title: PA28 pilot reported radio malfunction along with gradual loss of engine power.

Narrative: Problems starting aircraft. Attempted 3-4 times; then consulted [maintenance]. Tried a couple more times; airplane started with a loud backfire. Lost comm 1 at run up. Consulted [maintenance] again; just switched over to comm 2; finished my run up; and before takeoff checklists and took off. Got established and at 4500 feet cruising and leveled off and trimmed. Flight was beautiful until I noticed my airspeed started to fall. I was level and hadn't adjusted anything. I increased my power and it slowly kept falling. I leveled off again and it kept falling. I double checked my pitot heat. I pushed the nose forward to trying to increase my speed. It seemed to hold the airspeed; but as soon as I leveled off again it began to fall. During all of this; comm 2 went in and out. Center informed me ZZZ was right in front of me. I descended and landed without issue to myself or aircraft. Taxied off runway. I don't know what caused the issue.

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.