2007 LBZ, ATP tuned, everything else is basically stock. A few days ago, went out to start the truck and it wouldn't start. Had a lot of symptoms of dead batteries. Batteries tested both bad. Replaced them both and noticed the alternator wasn't charging for the first few minutes while driving. Replaced the alternator and belt today. Fired the truck up and it started charging fine, however that's when the problems started. The idle was higher then it was prior to the swap. The idle stuttered a few times then evened out. Took it for a drive and the desired fuel pressure was all over the place and truck was running terrible. Stooped and let it idle for a few minutes and everything cleared up. Took it for a drive again and the converter started to lock in second gear and stayed locked all the way through 6th. The up shifts were delayed as well as the down shifts. The converter would unlock in third gear when downshifting. The truck ran fine prior to changing the alternator. I have to imagine something electrical has happened, but I'm at a loss. I'm going to pull the alternator back out and see if anything is wrong. Codes were P0401, P0540, P0118, P0463, P0673, P0676. Pretty sure all these codes were here prior to the alternator swap. I've searched around but haven't found much as far as my symptoms are. If anyone has any insight I'd greatly appreciate it. Not sure if this is the right place for this, but mods please move as needed.
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