I was reading your comment above and fuel injectors popped in my head.

I like to use either Mercedes brand parts or whoever originally made the part. Example the Mercedes thermostat is stamped Whaler so id look for the Whaler brand to save money, I think the cam sensors may be Bosch.

Unfortunately i have no idea about fuel trims. Im not sure what fuel pressure should be for that engine.

 

And thankfully they are tucked under the intake manifold. So no simple swapping 3&4 with 1&2 to see if the problem moves with them. No touching a long screwdriver to them to hear if they are clicking. No unplugging them while the engine is running to see what happens.

I just wish there was a way to confirm before I pull the engine apart. I should have checked them when I have the manifold out last time. Oh well. Live and learn.

 

I was looking thru photos and it looks like my scanner has a test for fuel injectors. I have no idea what it does, never used it. maybe see what your scanner can do.