stuck valve on 5.7

My 1997 yukon has had an intermittant misfire that appeared after high throttle settings and then backing off. So up a hill with my boat trailer then at the top cough cough,

It finally stopped being intermittant

The 5 cylinder stuck a valve. $2500 later I am back on the road.

I think running Mobile 1 oil kept the wolf at bay for a few thou kms.

Auto forum said sticky valves years ago but I didn't believe it. I am now a believer