Thanks in advance for any help.
I have a 2006 2.2L HHR that is throwing a P0717 code. I changed both 02 sensors in February with Denso sensors from RockAuto when a code was thrown, I can't remember which code it was at the time. I replaced the EVAP valve and the code is still present. I recently changed the MAF sensor as well and cleaned the throttle body while also performing an oil change that was needed on Monday, the code is still present as of now. I've driven about 75 miles since the MAF change, I would think the code would have cleared by now if that was the issue.

Other threads suggest that the P0171 code could be from a bad fuel pump or broken flex pipe and I'm not sure which route to take next. The car starts fine and appears to run fine, I don't see any loss of power. It has and has always had a bit of a "putter" when first starting, almost sounds like an exhaust leak but I'm not sure. It goes away upon accelaration or after the car is warm. It's had that symptom since I got the car in 2020. I've recently noticed a stronger exhaust smell and the engine appears to be running hot. I got a "power steering" notification on the dash a couple of times upon startup, but it is not consistent. I'm not sure if that is related in any way, the car appears to drive fine. I don't see any codes for the power steering message.

I'm tempted to change the upstream sensor again with a GM part to see if I just recieved a bad sensor before jumping to a more expensive broken flex pipe or fuel pump. I changed the motor mounts last year.

Car has 197k miles on it. Any help is greatly appreciated.

Thanks.

 

Cn you just look at the flex pipe, fingers are good? Sure sounds like that is the cause of P0171, exhaust fumes are deadly. They usually crack on the bottom, cause is usually a bad motor mount; look through the oblong hole in the passenger side wheel house if you can see a bolt head centered it is good. There is only 1 "motor mount", on the passenger side the others are "transmission mounts".
For the power steering: look at the rear connection on the under hood fuse box, there should be 1 wire and be tight. Look at the fuses, make sure they are all seated. Tighten the 4 bolts in the under hood fuse box, even if they "feel" tight, pretend you are King Kong or Mighty Joe Young.

You cab "borrow" a fuel pressure gauge from your local big box parts store.

 

Remove the exhaust manifold heat shield, inspect exhaust manifold for cracks.

 

Check that flex pipe. Use soapy water in a spray bottle, check the rest of the pipe while you're down there. Mine broke clean off, right when I started it up one morning, but I had noticed a loss of oomph and a slight change in the exhaust sound in the week before it happened. Hope that's all you have to fix, good luck.

 

https://www.chevyhhr.net/forums/prob...hooting-66444/

My p0171 turned out to be a bad fuel pump. I had gasoline smell in the cabin when starting. Loan a fuel pressure tester from autozone and check the pressure with key turned ignition off, then pressure while running, and monitor the pressure for one minute after shutoff.

 

Should be 55-60 psi pump on, loose less than 10 psi in one minute after pump off. Pump will stay on for about 10-30 seconds when engine is off.

 

Thanks for all the help. I checked the flex pipe, I could not see any visible cracks or issues. I took the heat shield off the manifold as well and did not see any issues. While I had everything off I went ahead and changed the upstream O2 sensor. It was not very tight when removing, but not sure that had anything to do with it. The CEL did go off this afternoon, but that doesn't mean it won't come back. The reader still shows the code in the system last time I checked. I plan on getting a fuel pressure guage from the local autoparts store when I can and checking the pressure there. I do smell gas in the cabin occasionally. The car still seems to run fine, but that doesn't mean the issues with the pump aren't intermittent.

 

I didn't see any issues with my flex pipe, either, until I wiggled it. Soapy water will show you if there's something you can't see. There would also be a gas smell. I'm not saying this is for sure the problem, but you should eliminate the possibility before moving on, might save a couple dollars.

 

Post #1 says P0717 code.
Typo ?

 

The code will stay as "historic" for about 100 cold start cycles., The loose sensor probably caused the code.