Hesitation issue, car running poorly P0300, random misfire

My next step would be a compression test and then checking the injectors
try and have the fuel injectors clean

Should have the injector cleaned for sure
but the service should be to isolate and clean the injectors and not just add some cleaner to the tank, as you can do that your self
special top cylinder and fuel injector cleaner should be used
as recommended by the factory

also check this if it apply to you
STB

General Motors Engineering, in an effort to determine the root cause of catalytic converter damage, has determined that aftermarket alarm systems incorrectly installed in vehicles have the potential to cause misfire codes and damage to the converter. These alarm systems use a circuit interrupt which utilizes the ignition circuit on the vehicles.
These alarm systems utilize mechanical relays and normal vehicle movement can trigger these relays to engage and disengage the ignition circuit while the vehicle is in motion. These disruptions of the ignition circuit, which occur in milliseconds, may cause more fuel to be commanded. Over time, this dumping of fuel on and off again can cause misfire codes and ultimately damage the converter assembly.

If fuel pressure is good, then check that injector is firing, if you remove the connector and there is no change in the engine, then injector is not firing.

If SFI injection, check fuse for that injector.

A simple tool called a Noid light can tell you if injector is firing. They are available in sets at most autoparts stores for $20.

Remove electrical connector to #2 and connect noid light, crank engine, if light pulses, then injector or fuel, if it does not pulse, the PCM, Fuse, or injector, or wiring.

The module has failed. Replace it

Roy

Take car to some autoparts stores and get codes read.

If you can, check fuel pressure with mechanical gauge, and look at the fuel pressure regulator vacuum line for presence of gasoline.

Other than fuel and spark, you may have a clogged CAT or partially clogged.

Thanks for using 2carpros.

Engine running rough or misfiring can be cause by the following:
1.Defective spark plug.
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.