2002 gmc envoy p0300,p0756 2-3

2002
gmc
Envoy
4.2 liter L6 4wd

I have a 2002 GMC Envoy and it will not accelerate over 35mph. During acceleration the engine will not turn more that 2500 rpms or so. Also, during this the engine is running erratically. I thought it was a fuel issue but after changing the fuel filter, air filter, and changing the sparkplugs. Along with cleaning the throttle body and using the injector cleaner. The vehicle still will not accelerate. The codes I keep getting are p0014 camshaft phase angle error timing too advanced, p0300 multi misfire indications, p0756 2-3 shift solenoid . The engine idles like normal and while in park or neutral the engine will respond in all rpms. It only has these issues while the engine is under a load while driving.
The P0014 is for the cam position actuator solenoid. Basically it's how the PCM controls the valve timing. It sounds like obviously there is a problem in the system and it's keeping the cam retarded.....

There isn't too much to the system, PCM, cam actuator solenoid & related wiring but it will take a Tech II (factory scan tool) to diagnose properly.

The P0300 could be caused by the solenoid malfunction.....definitely want to fix that 1st before trying to diag the 300.

The P0756 is probably a bad shift solenoid, GM has some problems with those