PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Private
Flight Crew Last 90 Days 3.1; Flight Crew Total 163.5; Flight Crew Type 119.1
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft
On my return trip from ZZZ1 while cruising at 3;500 ft MSL approximately 10 Miles north of ZZZ.I was calling to ask for permission to cross their airspace; (although only 3;400 [feet] ceiling). During my communication; my engine starting running rough; and I had a slight loss of power.I told Tower what was happening and that I may need to land; I tried to gain altitude but did not have enough power to do so. Once I knew I had the airport 'made' under a no power situation; I tried troubleshooting with changing fuel tanks; trying carburetor heat; and changing mixture. Nothing changed the power I was getting. I still was getting 2000 RPM; which was enough to maintain my altitude.After the brief troubleshooting I informed ZZZ Tower that I did want to land Runway 10. The employees in the tower were extremely helpful; and their professionalism kept me calm. I turned for a one mile final and dropped in for the landing. The landing went very smooth; and the plane had enough power to taxi to FBO.This morning I contact mechanics on site; they towed my plane to their shop and discovered 'I Lost a Valve'. They are backed up a few weeks; but I will get more information from then soon.
Piper Cherokee pilot reported precautionary landing due to engine malfunctioning.