Transmission or ECM?

[M1Gunner]

Thinking about it... I did have a similar scenario happen to me a few years back with my Tahoe What caused mine to act up almost identically to yours was a very bad clogged converter. Kind of happened out of nowhere it seemed. The same accel issues the stuck in gear/"limp mode" I had a laundry list of codes thrown at me as well but I can't recall what all they were. I did get lean codes and it caused misfires and it was flat out horrible.
Not saying by any means this is what your tahoes underlying issue is, just random fun fact I guess...

 

[sumo]

Thinking about it... I did have a similar scenario happen to me a few years back with my Tahoe What caused mine to act up almost identically to yours was a very bad clogged converter. Kind of happened out of nowhere it seemed. The same accel issues the stuck in gear/"limp mode" I had a laundry list of codes thrown at me as well but I can't recall what all they were. I did get lean codes and it caused misfires and it was flat out horrible.
Not saying by any means this is what your tahoes underlying issue is, just random fun fact I guess...

It's too random of components that are not related. For the codes he had like solenoid issue and where he tried to replace the solenoid, trans fluid and still had no movement highly suggest it's a electrical problem. He's experiencing trans issues one moment and then misfires next thing and keeps jumping around.

Also recheck your battery cables, try moving them and see if you can make something like a misfire to happen while running. When moving them, do they feel brittle or crunchy? You can also try taking a razor and cutting a few inches back on the cable sleeves. Check for corroded or green discoloration on the actual bare wire cables. Also pull of the battery cable terminals. Check inside the terminals to seen if you have corrosion in the clamps.

 

[01ssreda4]

When a code like 757 is thrown expect a limp mode condition from the trans. Sounds like an electrical gremlin not a trans issue.

 

[daveypantele]

I double checked every piece of electrical I could get to. I checked all my grounds and they all check out. The battery is fine. In the process of pulling my plug wires one frayed apart and I replaced it and everything has been five EXCEPT the transmission. No more misfire. So I'm assuming that was my misfire issue. However, the transmission is still acting up. Now she will shift from 1-2 fine, and she hesitates shifting into 3rd and goes back to 2nd. If I toy with the throttle a bit, I can get third sometimes. But no 4th.

 

[Tacky]

I agree that withall the seemingly unrelated codes a bad ecm is a possiblity. All you can do is to check the grounds and wiring for codes that set, and if no fault is found, try an ECM.