I am new to the forum and hope I can get some help … I am completely stumped.

I have a 2005 Envoy Denali with 5.3l.
I am getting the 301 code and cannot figure it out. #1 Plug was wet when pulled out. All others look good. I have done the troubleshooting I know and am completely stumped.
​​​​​​- new plug
- new coil
- new wire
- new injector
- injector firing via noid test
- power at the coil.
- swapped all the above independently with #2 and problem stays in #1
- compression at 175-180 and good compared to others.

I read about the possible lifter or cam lobe issue, and pulled the intake and looked at rockers and intake and exhaust valve appear to be opening wide and well.

I searched the net for other things to try and troubleshoot but nothing.

Has anyone else had this or can someone give me some guidance on what to try next.

Hate tear into the head unless needed.

Thanks.

 

Well if the plug was wet when you pulled it out I would think a blown head gasket

 

Thanks …
The plug was wet from the gas not being burned … not from anti-freeze … compression is good on all cylinders and not losing anti-freeze.

more to come but for some reason I do not think the intake valve is opening and am suspecting the AFM lifter that allows the valve to open when turning the engine by hand, but then not opening when the engine is running.

 

Oh damn I thought AFM came out later on the Envoy sorry

Yes your AFM has probably failed. I would suggest deleting the system.

 

Turned out to be the intake AFM lifter on #1 cylinder.

I replaced it and all good now …

 

I would have replaced all of them on that side.

 

I did … sorry for not detailing that in the reply.

 

All good! My mistake if I read it wrong