CM870 High Pyro/Low Boost intermittent under load

[Peashooter67]

Check your egr temp sensor. I started having very similar issues and my egr tem sensor was reading all over the place and when it would spike way high it would cause the same issue.

I have straight exhaust so I could hear it before I saw it on the gauges.
The exhaust note would change then the manifold pressure would reduce and as the manifold pressure went down the egt would sky rocket.

I just learned this part, may be true with yours may not be. With insite my egr temp sensor is listed as ambient air temp sensor. I have a thread asking where this ambient air temp sensor is and no one has the answer.

So I starte unpluging sensors until I found it. Try unpluging egr temp sensor and also look at your other sensors.
Inlet temp sensor
Intake temp sensor
Intake pressure sensor
Barometric pressure sensor.

Also your exhaust back pressure sensor if it’s starting to go bad this will also happen.