So 20 seconds total?

 

@donkpow Yeah.

 

Are you consistently in open or closed loop fuel mode during these events?

 

@donkpow I didn't think to look at that I will tonight.
I'm a retired diesel tech. But gas drivability has never been strong point for me.
Thank you

 

Fuel trim numbers are calculated number values based on multiple inputs. They don't really indicate something directly. These numbers are a reaction to the engine not so much a report on the engine. So in your example, a stumble wouldn't be the result of changing FT values. It's likely that the stumble is the result of the ECM driving the idle speed down in a reaction to something it sees in the inputs. You could say like a loose A/F sensor wire or something like that. Or maybe a faulty read from the crank position sensor. FT numbers don't reflect a single misfire, for example.

OBD reports on the EGR valve position in real time if you have a scanner.

 

I'm wrong all the time. Is it correct to think a incorrect report from another sensor is causing this?
I forgot about Mode6 reporting a few miss fires on #3.; Not sure that means anything.

 

Okay. I may be on a fools errand. Stft -21.1 at lowest. System goes into CL and it immediately starts back to 0.

The stumbling was just concerning, maybe for no reason.

Thanks all

 

It sounds to me that you have a fault that the ECM concludes is not a fault. It may be the misfire. You can check your “pending” codes with a scanner. If you receive a CEL, I recommend you you also review the freeze frame data.

 

So far it's only the Mode6 few misfires.
I'm gonna keep driving it. Don't think it'll hurt anything. Maybe one day it'll jump up and say " look at me"
Thanks folks for all the info.