NEW GUY WITH ELECTICAL ISSUE.PLEAS HELP

91 CHEROKEE,4.0l,AW4 AUTOMATIC.Tranny was rebuilt last week.From a dead stop sometimes the tranny will not start out in 1.I think it is 2 when it does it or maybe even 3.Sometimes it won't shift out of 3.Also when starting up the jeep it will crank and not fire. If I pull the starter and ignition relays and the ignition fuse then put them back in it will turn over and fire.Turn the key and the needle on the temp gauge will register but after the engine is running the needle dies.The problem has to be electrical but I have no idea where to start.The only code that it is throwing is for an O2 sensor but that shouldn't cause all of this should it? Aslo tried a new TPS befor the rebuild and that didn't help.

not shifting sounds like either the tps or tcu.

the crank but not fire sounds like the cps

temp gauge sounds like there is a short in the wire

You should check the whole wiring harness for breaks, burns, or pinched.

Double check the braided ground strap from the head to the firewall.