Welcome to the forum.
Since that previous post, I've now come across this several times on engine-mounted GM ECU's and it's always been the MAF/IAT sensor's earth pin coming loose in the ECU's circuit board.
There have been posts on here and elsewhere, that say it's possible to just earth the dual sensor's yellow[?] wire and that sorts it. A repaired ECU is definitely preferable, but if funds are lacking......