Where do I start? Noisy, rough idle, poor performance, leaking oil
 

Hello all and thank you for helping. I just purchased thos 2006 HHR 2.4 and it ran okay for a couple weeks, but now is rattling so loudly I get stares while driving. Oil was. Hanged when I purchased it and I've had to add 2 quarts in less than 2 weeks. Codes are: C0561, P0011, P0101, P0128, P0171, P0014, P1174, P0366, P0326, P0300, P0137.

not sure where to begin. Any help would be appreciated.

Hi Rand, :welcomewagon: to the forums!!

Codes or no codes, I would want to know if it is burning that much oil, or leaking it out. If it's leaking, that could probably be fixed relatively easily. If it's burning that much oil, it may not be worth fixing, a new (or used) engine may be the best bet.

Keep the oil topped up for now, checking daily, until this oil problem is figured out.

With that many codes, I would be having the battery load tested, post up the voltage/amperage results here.

x2 what RJ said. How many miles on it?

You also need to figure out what is causing the rattling sound. The best and easiest way to check that out is to take it to a mechanic and let them figure it out. Trying to diagnose noises over the internet typically are a waste of time.

Driving it while it is rattling like you say, is not advisable. You can likely be causing further problems - and if the rattling is coming from the timing chain and it's tensioners, and they totally crap out while driving, you can kiss the motor goodbye.

My guess at the codes is a wire in the harness is broken/burned/frayed.

"rattling" means nothing to me. When,where etc? Needs adjectives.