Very randon CEL J200 with 21,000 miles

[BBBsti LTD]

I drive a 2015 J200 with 21,000 miles that while under very high load conditions (pulling a heavy trailer while taking off up a steep hill) throws a CEL. I have taken it to the dealer and the scanners reads multiple P0 codes pointing at the coils. The problem is that two coils were replace and the CEL came back on while driving under same circumstances (while taking off a steep hill while pulling weight). I went back to the dealer and they did a coils test by switching the coils that were throwing the codes and by having the technician on board with the laptop. We went for a drive and the truck threw again the code under same circumstances but on different coils. The tech registered again multiple coils codes on different locations.

This ruled out the coils, therefore the misfire it is happening but the dealer is having a hard time finding it. They did clean the injectors and went for another test drive and the CEL was on again under same driving conditions. At this time the truck is still at the dealership for diagnostic.

I believe they tested the ECU for resistance and came out fine.

Any idea or anyone with a similar issue regarding a random misfire that goes from one coil to another and on multiple coils at once.

Thank you