Anybody have any idea what might cause a rythmic, say ever 3-4 seconds sometimes misfire. Just a slight idle dip 100 RPMS or so at MOST on the bad days.. Idle wont stay perfect but its not by any means rough.

It did it both before and after the MS. I can't find any vacuum leaks. Can the coils cause a rythmic misfire? When trying to set the timing with it being locked at 10* BTDC in MS, every time it missed the timing seemed to jump a degree or so.

Its not causing a huge problem yet, but I'm curious if you guys have any suggestions as to what to check.

 

My highly uneducated opinion is a dying CAS. What plugs do you run? What gap? What AFR at idle? What timing value? Every datalog this? Perhaps a bit of noise is triggering ASE.

 

Stock plugs, unsure of gap. ~13.1 at idle, I'll check a log and post one up.