First time asking a question. Need some advice

Truck has 67K miles and has been to the shop for a $1000 plug change , numerous coils , clogged cat from the misfire before plug change. I took truck back to dealer due to the rough/low idle and engine/valvetrain noises. I last seen the flashing engine light at about 70mph when I went to pass a truck. The light flashed for 30seconds , truck kept misfiring but did correct itself and the light turned off.

I have asked the dealer the following , of course they cannot find anything wrong - Valve lash adjusters? , Compression test? , Coils?