CM 870 idle issue after start up

[Craag]

(03-25-2021 )Rawze Wrote:  air getting in the fuel system?

I had thought of that too it's distressing when you show or tell a certified diesel tech that they don't automatically think it too as I'm by far less qualified. My only question I had to that is why it's fine first thing in the AM after sitting the night?

After I start the truck it idles then it kind of revs itself up a tiny amount 10 or so seconds later as if I touched accelerator them settled in its normal idle. That is normal for past seven years. Now when it goes to do that little rev it's like it gets stuck in it repetitively attempting it. Almost like a little whine sound like a turbo spinning when it happens too. I almost wonder if it's ecm related?