2009 SLT Yukon rough idle for 30 seconds on cold start

[dro45]

Spark plug(s) wet with oil? Needs a catch can and the updated valve cover?

Spark plugs new, and look perfect. Wiring new.

 

[dro45]

Try cleaning the MAF and Throttle body first...
Then my next step might be to verify fuel pressure and check intake manifold
for possible (probable) vacuum leak...

I'm going to try this.

 

[dro45]

Gotta verify what your fuel pressure is at idle and under load or it’s scan time. Have you replaced the f/p or is it a generic fuel pump? So many things it can be without using the power of the scanner force.

Thank you. This and cleaning the MAF will be my next steps.