I've had the valves adjusted every 110,000. Car is still a little groggy but not near stalling. the AC really drags it down whilst idling.

 

Plugs/Coils/Valve adjust between 60 and 80 K depending on Low or high speed operation. JUST DO IT its a maintenance item.. Solid valve train needs regular love.. All waiting does is means you get caught when its least convenient ...

Plugs really should be inspected every 20K or so and checked that they are not loose.. Its too easy to do to (< 30 minutes) to let a plug blow out and destroy/damage the head.. Which is a real issue on the fit.

 

I found a I found a considerable amount of residue and oxidation on the ignition coil boots inside specifically on the spring contacts. As a free option, consider cleaning it out with some isopropyl alcohol to see if that restores your original electrical conductivity. It's a heavy amount of white powdery oxidation residue that I'm sure isn't helping the electrical conductivity. Just be careful because the plastic has gotten a bit more brittle after years of heat exposure.