Stuck lifter or valve?

Long story short, used to have intermittent rough running after a heat soak, it has made itself a little more apparent now. When starting from cold it has a miss (like a dead cylinder) and a loud tapping noise that corresponds to the miss. Once warm it goes away and runs smooth. I am currently running 15w40. I seafoamed it a while ago and it helped with the hotsoak miss. I have a shortblock and a new head to install one day when I have time and a warm place to work. Any tips on a temporary fix? Thanks

mechanic recommened drain oil, refill with atf -idle 10 minutes, drain and add new oil-- bad idea??? he said atf is high in detergent and will not hard the engine at no load.

I wouldn't put full ATF in it, it's just too thin for the rod and main bearings.

I've seen the old timers around here do 50/50 for a couple of minutes to free a stuck lifter.

Change the oil/filter( leave out one qt), add a qt of MMO, run it a couple of weeks and do it again.

MMO= Marvel Mystery Oil

I've used a quart of ATF in my oil to try and free my sticky lifter, but I think mine are too far gone and the problem is really that they don't always stay primed up, not that oil isn't getting in.
When I put ATF in my crankcase I just drained a quart, replaced it with ATF then gently drove it for around 50km. Got home and changed the oil while at operating temps (just don't scald yourself). The oil came out very black which surprised me since I had changed the oil not too long before. Long story short, it didn't fix my ticking lifters, but sure cleaned the internals out..when I pulled the valve cover off a while later everything was nice and shiny.

Did the atf trick last night, 1 liter 15w40 and three liters atf, let it run 10 minutes, drained the oil, changed the filter, refilled with 5-30. And I drove it for a while last night (mudders suck on the ice). Bingo no lifter noise and no chugging/ missing this morning. I'll do another oil change tonight with 10w30 and see how it goes.ATF works!!

What kind of ATF did you use? I've heard there is one type in particular that is really high in detergent...can't remember which one though.

I was told Type "F" has the highest detergent level. This was from someone on this board that is familiar with using it for this purpose.