Just a quick one, I understand that the spark plugs were changed but were they "gapped" properly, before installation?
We went down the rabbit hole of EGR related issues but it was as clean as a whistle.
The rear plugs were all totally worn out and it appeared that they had not been changed since the car was new, this was possibly about 10 years ago now.
After fitting a complete set of 8 plugs the problem did not recur.
When the hickup-issue occurred the first time (coulpe of years before), replacing all spark plugs resolved the issue back then (mechanic showed me the spark plugs, especially the rear-lane plugs had been fully worn because they hadn't been replaced with a former spark plug replacement). Back then 8 new plugs were fitted, and the car had been driving well for quite a while (more than 1 year from recollection, I think I covered the timespan more detailled in the opening post).
From the mechanic, I understood that with the "most recent" spark plug renewal (together with the ignition coil that was broken in half), the same brand/type of spark plugs were used as before, so I think íf any "gapping" were to be applied, they would be "properly gapped" off-factory, or had been done well both times.
Replacing the remaining 3 ignition coils on the backside (with the same spark plugs from the last service) resolved the issue for me. I haven't had the chance/time to open/inspect the 3 ignition coils that were taken out (I have them at home), will see if I can inspect/post some pictures that could support my assumptions.
Stop firing the parts canon, find a local electrical technician go from the report supplied.
I tried to do that by contacting a local Honda garage, but their advice was fairly quickly pointing to spark plugs / ignition coils (together with the other "issues" from the opening post like throttle body grounding). I don't think they would even consider doing a "electrical report" prior to having a look at the "known issues" from the opening post (probably easier money for them as well
).
