Fuel injector question- OK at idle only

[Cranky]

Some of the local police departments are still using Crowns and you know they must have a million miles on them lol

 

[Darthomas]

Developing story....No. 2 cylinder exhaust valve had locked in place and was not rotating. Heavy treatments of Sea-Foam broke it loose. But it now has heavy, uneven carbon deposits on that ex valve seat. As the valve rotates in operation, the cylinder efficiency and engine smoothness is quite variable from second to second. I have no idea how many thousand miles that valve was locked in place. I seem to imagine it's getting smoother as (hopefully) carbon is now wearing from the seating faces.
Much smoother pull in torque-up @ 1500 rpm. Can still hear "putt-putt" in pass side exhaust....but it's much smoother warmed up in idle. Anyone else ever have a carboned-up valve reseat OK aftera few thou miles?