2007 hummer h3, throwing p0300 and p0017 codes, has a small ticking sound when it turns on, then worsens as it gets warmer, sane with the misfiring, starts small when cold then it worsens when it gets warmer and eventually it'll idle rough and stall/die out. I have to constantly keep my foot on the pedal where the rpm is over 1,000 to keep it from dying out. I've changed numerous amounts of parts and it still stalls and gives out the p0017 code. TIA

 

Welcome.

Can we please have the list of parts thrown at the problem? How about miles on the 3?

Have you checked the the intake manifold fasteners are torqued to spec. How do the exhaust manifold and its fasteners look, as in are all the fasteners present and can you see any crack(s).

May we assume you recently changed the oil and it is at proper level?

Have you checked the camshaft actuator solenoid and look for crud on the sensor, on the screen in the motor, or a missing screen... replace if necessary, tighten mounting bolt to 10 N.m/89 lb in.

 

Put down the parts cannon sir or Madame and back away gracefully. This will seldom help find the issue and quite frequently causes more headaches lol!

Lets start with some stats and then get a baseline as to what is the real cause.
Your going to need a proper scan tool and maybe a scope. Also, I'm going to suggest looking at a great case study done at SMA garage on youtube. Mr. O covers this in great focus and length on a Collie Canyon with the i5 engine.
It is not my content, nor do I know the individual. I just feel it might help with your issues.



https://www.coloradofans.com/threads...engine.283521/