I was driving home on the freeway on Sunday night when I started to hear some sounds. It sounded like it was coming from the belts. It would come and go, more rhythmically than random.

When I got home a few miles later, I shut the car down. When I restarted, it would idle around 1000 and then rise and then back down to 1000. This would continue but soon it would hit a higher idle and then return. Eventually, it would hit 2000 and stay there. That's when I shut it down. I drove the car the next day, and it hit 4000. At this rpm, there is a consistent sound from the belts. The Check Engine Light also came on. I can't find my obd reader, so I haven't pulled the codes yet. I'm also hesitant about driving it.

I uploaded a video where it hit 2000rpm . https://drive.google.com/file/d/1M0g...ew?usp=sharing
Car is 2015 V60 with just under 32000 miles.

 

Yup, the crowd favorite P0171. I tried to pay attention to the sound. The sound is only there when I'm not giving it any gas. O'Reilly's had a nice scanner. If any of the 42 points of live scan data is helpful, let me know. I took a video while scrolling thru the data.

 

The belts seem like a different issue than your code, might need to be replaced. Get in there and check the fuel pressure, make sure its in the correct limits. Check boost pressure to check for intake leaks. Smoke test for intake leaks is easy enough as well, I use the small hose coming off the intake.

 

I replaced the oil trap, and the rough idle and sound went away. CEL has not come back yet, but I also don't drive much now ...