2003 Sierra 1500 weird problems

[Archer3d]

Hello I have a 2003 Sierra 4x4. Had the battery go dead, door jammed open on seat belt. Computer reset now it won't complete the cat test or the evp test. 4 weeks. Tried reseting computer no joy. Repeatedly done the drive cycle according to gm. The dash is also crazy in switching languages all by itself. Engine won't idle right until cat test completes, have to left foot the brake to keep running. Have pulled the ecm and checked all connections and grounds all seem good.

Sorry for long post. Looking for any ideas suggestions