Strange shifting & Idle issue

Sounds like I'm gonna have to test my TPS with a sort of similar issue I'm having.

I understand the updates are irrelevant. The car sure runs, idles and shifts better though.
A scan is showing a problem with the Output driver modules in the new PCM from ZZP.
I imagine due to of lack of communication as you said. I wonder if this has any effect on other various electronic outputs?

We'll see how it goes later today.

USPS showed up with PCM. Installed it and Trac Light Off is now Off.
Comes on when pushing the button as it should.
Time for a little ride.

Good in glad it worked the way it's supposed to!

Me too..
ZZP said to just toss the other PCM.. It's obviously a bad core.

Maybe you have a similar issue with yours Swiggles?

No the impalas work a little different with the electronics, I've looked into and don't want to pay the dealer to do it. My stock Pcm works fine, we just didn't know if it was modded or not when we put the motor in so I didn't use it right away.

Went for a good ride yesterday to my brothers in northern MA. About 1hr 45 min each way.
He gave me a hand installing the LCA's and outer Tie Rods. Wasn't bad at all with air tools. No problem removing the T-55 Torx bolts either.
Anyhow, their were no shifting problems at all the whole trip. Actually seems to improve (learning?) the more I drive it.
Also noticed the blinkers are working correctly as well as the Auto-Dim mirror.