2008 HHR ss. Having problems with misfire at high rpm. When boost builds and the car hits 4000 rpm it studders and won't gain rpm changed spark plugs and cam actuator solenoid. Any help?

 

Welcome to the site.

Pull the codes from the OBD system and see if it shows any trouble related ones. Post them here if it has any.
Stating the mileage would also help.
Actuator solenoid. Just 1 or both of them ?

 

Welcome to the site, what plugs you use?

 

PO100 mass air flow circuit fault
123k miles
Intake cam solenoid

 

Autolite extreme performance

 

I'd suggest going to the OEM AC Delco iridium plugs, the engine was designed for them.

 

X2 on that.

By that code I would say your MAF is either dirty or has failed. Are you by chance using a oiled K & N filter?

 

You didn't think that the CEL was worth mentioning?

It is P zero 100.
https://www.obd-codes.com/p0100

Was the air filter been replaced just before this started?

 

On an SS I don't believe the MAF sensor needs to be disconnected, however it could be loose or dirty!

 

If it is a stock location airfilter housing it does not.