I really need help with my 2008 Chevy HHR SS, I don't know what to do

My 2008 Chevy HHR SS is struggling at idle and running ridiculously rich. I scanned the check engine light, and a bunch of codes appeared, but I’m lost on what they mean or how to fix it. This is my daily driver, and I need help figuring out what’s wrong. Does anyone have any advice or similar experiences?

Can you share what codes you’re getting? That would help a lot in narrowing it down. Running rich could be a fuel issue, like an oxygen sensor, MAF sensor, or fuel pressure regulator.

Lior said:
Can you share what codes you’re getting? That would help a lot in narrowing it down. Running rich could be a fuel issue, like an oxygen sensor, MAF sensor, or fuel pressure regulator.

Yeah, I got P0172 and P0300. Not sure what they mean though.

@Micah
P0172 means your system is running too rich (bank 1). P0300 is a random misfire. These might be related if it’s a fuel delivery issue or bad sensors. I’d check the mass air flow sensor first and maybe clean it. Also, how long has it been since you changed the spark plugs?

@Lior
Haven’t changed the spark plugs in a while, maybe that’s a good place to start. Thanks!

Have you checked your vacuum lines? Sometimes a vacuum leak can cause misfires and make the engine run rich. Might be worth inspecting those too.