On your wave form showing the WPS in the exhaust.
Is it feasible that due to the length of the exhaust that the cylinder showing the high pressure is from number 4 cylinder.
i.e. time for the pressure to travel the distance of the exhaust.
If so is it possible that what you are seeing is the exhaust stroke from number 4 and compression from number 1 cylinder with an exhaust valve sticking open.
Not sure about waveform showing running compressions.
Hope I've made sense!
HTH
David
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