Try GM fuel system treatment plus #88861012!

 

Just took it to the shop. Cylinders 1-3 are roughly 150psi. Cylinder 4 is 90. No estimate given, this shop doesn't do internal engine work. Looks like it was worst case scenario.

 

Head gasket? Burnt valves ?
I have to ask if they don't do internal engine work, why is it there?

 

I suspect a burnt valve based on my research. No oil in the coolant or coolant in the oil. I don't seem to be burning any oil or losing any coolant either.

I went to the dealership and talk to the service writer but they could not fit me in until next week. I talk to him about the codes I am getting and he says that it is almost certainly something internal with the engine or a computer problem.

I took it to a independent shop with a very good reputation locally. I Drive too much to postpone having this problem looked at any longer.

Right now my plan is to rent a car and leave the HHR with my regular mechanic next week.

 

K , let us know how this plays out!

 

My mechanic confirms burnt exhaust valve on cylinder 4. Taking the head to a machine shop and I will update once I know more. Thank you for all of the help so far.

 

You're welcome.