2008 LT Auto 2.2
Today after our 12' dump of snow I got stuck in the driveway.
While trying to get out I noticed that it was lazy off the line in reverse.
Seemed totally normal in drive but in reverse it seemed to be in limp mode and then would eventually rev up. No lights or messages whatsoever.
Any ideas.

 

Could just be the cold! Or throttle body dirty and icy!

 

If your car has traction control it may have been reducing power to save it from damage.

 

I'm with Lucky in thinking it was just the traction control kicking in to retard excessive wheelspin, that is as long as your HHR is T/C equipped budzone.

 

No T/C guys and should not be from cold. It seemed perfect in drive.
Only seemed to be in reverse.

 

after sitting over night how is it today? same or back to normal

 

Well, now that T/C is out of the equation, if you were trying to "rock" it out of the snow by going from Drive to Reverse rapidly, it may have triggered the transmission's overtemp protection mode to keep you from frying it.

"Rocking" stuck vehicles out of snow or mud puts a tremendous amount of stress on the drivetrain, it's a great way to kill a transmission, snap a halfshaft, or even cause a tire(or tires) to explode.

 

Actually the way I noticed it was by pulling ahead as far as I could and holding it there then shifting to reverse. Trying to capitalize on what movement I had. When I tried to go backwards I kept losing all free movement before throttle would respond. Going forward again throttle was right there.

 

There is Torque management code in the ECM to protect the transmission, sometimes it's called torque management and/or Abuse mode. Like for instance my truck, the brake stall RPM limit was 2000 RPM enable, 1600 disable. Which means no brake torquing.... now where is the fun in that I ask. Fixed that

Just looked at a 2006 auto file, they have trans abuse mode torque reduction duration/time vs trans temp. There is a Drive ramp out of 1 sec and reverse ramp out of 1.5, My interpretation of that is neutral slams or drive to reverse to drive again. My guess is you were in the Trans abuse mode Torque Reduction vs RPM. Generally what happens is the TB will start closing to limit the torque being applied through the trans, preservation mode...

FWIW the brake stall torque RPM enable is 900 RPM, disable 800 RPM.

Thought maybe this might you understand what was going on.

 

My 08 1lt Panel does not have traction control BUT if the tires slip to much in the wet, something kicks in and reduces the power to keep it to a minimum. You guys know way more about this than I do but sounds like it could be a factor with the OP's issue.