Best way to diagnose misfire

[BSouders80]

If there is a misfire on a cylinder, will it 100% of the time throw a CEL? I've got a little bit of a rough idle. 6.6L + SC.

I have Forscan, but don't necessarily see a misfire test there as shown in some of the Forscan youtube videos.

It could be a dirty MAF sensor?

What methods would you use to check this out?
I did do a log and sent it to Livernois to check out. That will take a while to get feedback on though.

TIA!

 

[BSouders80]

I did the KOER test today with my tuner from Livernois. With Forscan and Livernois tuner, I keep popping for P1101 - MAF sensor out of self test range. I pulled the MAF sensor and it looks clean as a whistle. I went ahead and hit it with some contact cleaner then used compressed air to dry it out. I believe same thing. On the tuner, it has an option to display some data tags. I can pull in the values from MAF Sensor and the values do change. In the low RPM's, the MAF sensor value is in single digits and as throttle increases, the number goes up. When I went with the 6.6L from livernois, the installer had to do some re-wiring. If I remember correctly, factory has IAT and MAF from same sensor???? But Livernois needed IAT and MAF on separate circuits. The plug on the MAF sensor looked very clean on pins and plug. I'll try to trace back the wires and see if I can find where they did their "re-wiring". Any other thoughts?

 

[Marlboroman]

You’re in waters few have explored with that setup. I would make sure whatever they tapped into can handle the additional load in addition to the connections themselves. I’m not the best electrical guy by any means but I think you’re on the right track. I’d stick on the electrical path after verifying the MAF is not compromised. Keep us posted.

 

[V1ROTATE]

Forscan mode 6 should show all the data you’re looking for. Just have to sift through each cylinder