P0300 code on 2004 GMC Yukon XL Denali - 119,000 miles

[zaahirkhan49]

2004 GMC Yukon XL Denali - 119,000 miles

Have had a P0300 code for a while now. Changed everything from spark plugs to lifters, cleaned as much dirt and carbon off the engine, but I still get the same code. After driving for a while, there is a noticeable shake / vibration at idle. Also, all of my monitors seem ok except for the EVAP system monitor, so I am guessing it must be an EVAP related issue? I have pretty much run out of options at this point and am left with the option of just replacing the entire engine. Is there anything else I could do before going that route? Maybe I have to redo the crankshaft relearn? Also, I do get a faulty knock sensor code too but that goes away so I don’t think the knock sensor is an issue but I will still take another look at it. Any advice would be appreciated. TIA!

 

[Fless]

Definitely do the CASE relearn just to rule it out.

Throttle body been cleaned lately?

What do your short- and long-term fuel trims look like?

 

[zaahirkhan49]

Definitely do the CASE relearn just to rule it out.

Throttle body been cleaned lately?

What do your short- and long-term fuel trims look like?

How do I do the CASE relearn?

Throttle body was cleaned out within the last two weeks, when I replaced the lifters.

I also changed the fuel pump already so i’m guessing the fuel trims are ok. I do not have the proper scan tool to see the fuel trims.