2001 Pontiac Montana erratic RPM, randomly dies

Got a 225k mile Montana with the 3.4L engine that is experiencing random performance issues.

The engine got a head gasket and lower/upper intake gaskets about 8 years ago. The ignition control module was replaced about 2 years ago by the previous owner for similar issues but it never really cleared it up. It seems to be worse when it gets warmer outside. The van will try to cut out and lose power and the RPM gauge will go crazy while driving at lower speeds. At 50-60mph, the RPM’s will fluctuate smoothly with a 100rpm range or so but I know this is an issue with the TCC solenoid which is a common issue in this transmission. Sometimes when not in motion, it will just die with absolutely no warning, like someone turned the key off. It always restarts immediately with no issues. Fuel pressure is about 46PSI when running, 48-50 with key on. It does not lose pressure when turned off. The only code it had was a pending P0446. I tested the fuel pressure regulator, it did not leak and there was no gas in the line. I have 4 kids and this is the only vehicle I have to haul all of us so I would appreciate any insight. Thank you in advance.