PO741 Fault 2013 Ford Escape

Question

Recently had the wiring harness replace, ran well for 2 weeks, then started missing and loss of power (Reason wiring harness was replaced) Ford shop said my transmission was bad, wanted 5k just to look at it, took it to my 5 star transmission guy, he says h transmission is fine, and that I have a wiring problem.

Looked online, other people with the same problem have had their transmissions repaired only to have the same problem in 2 weeks.

Any suggestions on how I should proceed ??