year's long random 2007 Magnum 5.7 R/T trans issue

[JetsNeedNewton]

This is probably not a Diablo tune issue, but it's involved:

Anyone experience this or have ideas?

Initial symptom: When paused at a stoplight, the trans drops into some neutral mode when I try to move forward. Gear status on the dash disappears. Solution: Turn off engine, put in park, and restart. Problem solved. Sometimes no more issues for months, other times frequency of issue increases.

Worst case: Problem grows to where I can't go over 2900 RPM on highway. Dash view of what gear I'm in disappears, trying manual shift to other gears changes nothing. Once or twice it's gotten so bad that when I get off the highway trans drops to a lower gear while still maintaining the 2900 RPM limit. I have to pull over and reapply my last Diablo tune. Then back to normal for a few months.

Diablo tunes: CAI, Cold Thermostat, 93 octane, Performance Catalytic Converters

Other info:
- one time, my Mech took car to Dodge who said Trans tables were all screwed up, reset them and I was back to normal
- This is my second ECM, might be the problem
- Mech says it might be trans solenoid messing up the ECM. But there's two, one external and one internal to the trans. Major price difference to check
- Mech also thought, uneven power to ECM might be the issue, fixed the power problem, but issue came back.

Love to hear from you all who experienced a similar issues or just might have some idea's.