Saturn Vue 2003 3.0 Misfire

I have a 2003 Saturn Vue 3.0L FWD which had a P0303 code and is definitely misfiring but does smooth out at higher RPM's over 2,000. I scoped the cylinders in Bank 1 and have the below waveforms which are consistent with the P0303 code. It is impossible to swap coils or get direct access to them to verify if the coil is bad as they are located under the plenum and are part of a bank of 3 COP's.

If I am reading the waveforms correctly, it appears that the coil has a short in the Primary due to the beginning hump and the Spark Plug is shorted out due to no spark line after the spark event. At higher RPM's the spark line does start to appear (Waveforms below were at idle.). Since the entire Plenum has to be removed just to get to the coils, I wanted to confirm that my analysis is correct that it is indeed a bad COP.

If I do replace then I will replace both Coil Banks and all spark plugs since it is labor intensive to just get to them and there is 168K miles on the car.


Misfiring Cylinder #3 Waveform


Good Cylinder Waveform

That is not a shorted primary winding, it is a shorted secondary. Either way, change the coil AND the plug if it lives under the intake. Nice captures!