[hatcherpass]

Curious if anybody else has had a similar type experience.
Subject is a 2014 X1 35i that I purchased used with about 4200 miles (4.2k not 42k)
Put about 2000 uneventfull miles on it and install a JB4 piggyback tuner on it.
Ran an additional 2000 or so miles without issues then, out of the blue driving home one day on cruise control at about 60mph, I get a a tiny stumble like it is starving for fuel. It recovers, I continue on. A minute or so later it happens again a little worse. Recovers again and procede.
Then, happens again, worse still. Engine light comes on and I pull over. Engine is stuttering and stumbling. Turn engine off and restart. Runs fine. Pull back into traffic and right away it stumbles again but now I have the check engine light, the "gear" indication, the "service lift" indication and it seems to be stuck in 3rd gear.

Long story short, make it home bucking and jerking. Disconnect battery, and the next day, everything is fine again. Now driven an additional 3500 miles without issue.
My initial thought was the JB4. Checked the wiring and all seemed fine. The CANBUS wires are soldered on so I am pretty sure that is not a factor.

Still sort of don't trust it even though it has been fine for several months...