Hanging Harness/Weird Idling

[Cody Evans]

So I noticed in between the driver and rear seat of my 2017 Chevy Silverado 1500 LT underneath the truck was a harness hanging there. I looked up the part number to see what it's purpose was, because I couldn't find anywhere it plugged into. The part number is PBT-GF30. Can someone help me with this?  Also my truck is idling in between 500rpm to a little over 1,000rpm when the truck is in park. I changed the intake air flow sensor but didn't do the trick. 

[silveradosid]

the plug is for a flex fuel sensor. how many miles do you have on the truck, might be time to clean the throttle body

[Cody Evans]

I have 97000 miles on it. And I can see that for it being for a flex fuel package.

[diyer2]

I would try fuel system cleaner. Easy. Cost effective. BG 44 k would be the strongest IMO but cost the most.