[HawkX66]

Nevermind. I just found this which describes what happens with a bad seat.
"The other common type of valve failure is valve burn, or burnt valves. Essentially this is caused by combustion gases escaping between the valve and valve seat when they are not sealing correctly. The hot combustion gases are forced past the valve which starts to burn away the edge of the valve, progressively getting worse the longer it is left without being rectified. Normally this type of failure affects the exhaust valves only, but it can also damage the intake valves.

A burnt valve will cause issues with your vehicle’s performance and fuel consumption. Rough idle, reduced power, backfiring, and misfire are all symptoms of valve burn."