98 rodeo wiring problem

i have a 98 rodeo 4x2 and transmission light comes and goes for last month/ mechanic checked it said speed sensor not to worry, then yesterday alt/brake/and tranny oil temp light lit up on it and it ran like it was being held back, parked it at work and 8 hrs later it started up and ran home with NO problems? also have a turn signal issue with them sticking on at times...not always ... and check engine light that comes on and code say O2 low voltage... is any of this related or should i just retire this rodeo now?

Test your alternator properly.