2008 Chevy HHR 164,000 miles

I have a p0171 code that I cannot figure out how to get rid of. Also has trouble starting up the first couple times you turn the key. I've replaced the MAF sensor, the MAP sensor, the EVAP purge solenoid valve. Replaced the spark plugs. Smoke tested for vacuum leaks and found nothing. The STFT and LTFT are much better since replacing the sensors, and at one point I had actually thought I fixed it because it was starting right up and running really good. Initially the idle STFT was-3 and LTFT was 28. After changing the MAP sensor the STFT was 0 and LTFT at 9. That's when I thought everything was good and I probably started the car 20 times with no problems and fuel trims we're staying the same. Then I cleared the codes with my scan tool and the car died. And then it went right back to having the same start up issue, but the fuel trims are still the same. I did a test drive and check engine came back with p0171 with the LTFT really high at freeze frame at about 23 I think it was. I did forget to mention after I changed the MAP and it started right up, I had forgotten to plug the electrical connection back into the MAF. But when I noticed it and plugged it back in it seemed fine. Not sure where to go from here.

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According to this article, there is still the possibility of a cracked flex pipe, and or a faulty fuel pump!

https://www.obd-codes.com/p0171

 

Fuel pressure?

 

Many big box parts palaces loan or rent fuel pressure testers , usually for free.
the intank fuel pump, fuel pressure should be 55 to 60 PSI for an LS or LT model

 

Thank you for the responces. Im not exactly a mechanic by any means and this is my first time doing any of these things. I will check out the fuel pressure and post back. I was gonna try that initially, but i was thinking the fact that it was running better and starting right up, for that 30-45 minutes before I reset the codes, that it for sure had to be a sensor problem or maybe an electrical issue. I will post back after I check the fuel pressure. Thanks again!!!

 

Not sure if this is what I need to look at? But I figured I would post these numbers from my scan tool while I figure out how to test the fuel pressure. I just now found a tester that I bought from the parts store.

 

 

this is the fuel pressure when car is on at idle. I can't get any pressure if I turn the key to the on position. Only when the engine turns over. And as soon as the engine is off, the pressure does not hold and right back to zero. Is that normal?

 

No, that's a bad fuel pump, a seal.

 

I do hear the fuel pump turning on when I turn the car to the on position and the pressure starts to try to fill for a couple seconds. But then turns off and all pressure is lost.