Hello All,

Growing frustrated and ready to give up on this car.
2006 Chevy HHR 2.2L
203,000 Miles

I've posted before about similar codes, but I am continuing to have the same issues. I've replaced the O2 sensors now 3 times, this most recent time replacing the upstream and downstream at the same time with GM Genuine sensors. I've replaced the throttle body gasket and cleaned the throttle body. I've replaced the MAF sensor as well as the EVAP valve. I've tried fuel treatments.

The P0300 Engine Misfire code is new, but the P0171 and P0131 codes have been consistent. The intermittent code P1133 is fairly new as well. The last time I changed the sensors the upstream harness had what looked like coolant in it, but I do not notice any leaks or loss of coolant. I've checked and changed the fuse in the 33 location. I've inspected the flex pipe and do not see any visible cracks but I'm tempted to try and replace it if I even can myself. The pipe to the throttle body seems to be okay as well. The spark plugs were replaced at 183k miles with ACDelco 41105 spark plugs, I may need to replace with 41103.

The gas mileage drops significantly when these codes are present. The car has always had a sort of "puttering" sound upon startup, but goes away after a minute or so of idle. There are ocassional exhaust fumes but not consistent. The car starts just fine each time, cold or hot.

Any help is appreciated. I'm tired of throwing parts at this and I'm tempted to take it to a professional.

Thank you,

Nick

 

They are all related. I would suspect the wires to the upstream O2 sensor or the connector. Look for the wire laying on the exhaust and melted and the connector for pins bent or not connecting.

 

First , change those spark plugs to 41-103. Then tighten the 4 bolts in the under hood fuse box.
remove the air box and heat shield over the exhaust manifold and inspect for cracks. Check your fuel pressure.

 

I will go ahead and replace the spark plugs. Crazy that Advance says the 41103 does not fit a 2006 HHR but I know from reading on here and elsewhere it is the right part. RockAuto does not even show the 41103 under the part options for the car. Knowing the what sounds like an exhaust sound and the ocassional smell of exhaust is it worth replacing the exhaust assembly? I would like to avoid a welder so a kit that includes the flex pipe and replacing the whole thing would be better.

 

If you can get a catalytic converter for cheap you could replace the downpipe, it is an assembly. Some people have had good experiences with cheap cats, others not so good.

 

RockAuto lists this kit from Walker, but from the pictures it does not look like it includes a flex pipe:
https://www.rockauto.com/en/moreinfo...10727&jsn=1134

 

Looks like this is the part I would need if i went with Walker, a little pricey: https://www.rockauto.com/en/moreinfo...=5808&jsn=1137
Assuming since the '06 upstream sensor is located before the flex pipe I would need a plug for the hole after the flex pipe on this one.

 

That’s one but there’s others

https://mufflerexpress.ca/products/c...rter-2005-2007

Or just the flex pipe and this clamp on kit

https://mufflerexpress.ca/products/c...pair-2006-2010

Or even less popular

https://www.autoshack.ca/EM64809

Still a good choice.


But before you order anything investigate the exhaust manifold for any cracks

 

Thanks for all of the help. I will look into those.
After thinking about it, if the upstream on the 06 is located in the exhaust manifold, is the lean condition code reading there or in the downstream sensor after the cat? I inspected both the flex pipe and the exhaust manifold a while back and did not notice any cracks.

Nick

 

Like this



It was hiding under the heat shield, see the yellow arrow