Engine noise, reduced power, slow response when accelerating, codes P0019, P0171, and P0175

2008 GMC ACADIA
170,000 MILES • 3.6L • 6 CYL • 2WD • AUTOMATIC
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DONALDLEIJA608
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Just last month my engine started to make a horrible knocking noise. I have had the vehicle scanned and three codes have appeared P0019, P0171, and P0175. I have checked fuel pressure and its within speck at idle and in gear. At this point I'm not sure what could be the problem.
Mar 26, 2019 at 2:01 PM
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JACOBANDNICKOLAS
  • ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
Welcome to 2CarPros.

The definitions of the codes are as follow:

P0019 - Camshaft / exhaust camshaft bank 2 correlation error

P0171 and P0175 both are related to a lean condition which means the engine is getting too much air and not enough fuel.

Now, I'm concerned that timing may have jumped on the exhaust cam. Take a look through this link and see if what you hear seems to correlate with anything in the link.

https://www.2carpros.com/articles/engine-noises

Next, most lean fuel conditions are usually related to a vacuum leak. With that in mind, here is a link that explains what can cause a leak and how to check for one.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know about the noise and you may want to check for vacuum leaks.

Let me know what you find. Also, if you could let me know approximately where you hear the knocking sound from on the engine, it would be helpful.

Take care,
Joe


Mar 26, 2019 at 6:36 PM
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