EXhaust tone changes while cold idling
I have been looking for a truck for the past little while and I looked at this one today that I liked but... It was already started when I got there and the guy said it hadn't been running long and from the looks of of it I belived him. It seemed to idle fine but the exhaust would changed tones every second or so and sounded like the ebpv was opening and closing. He said it was just the exhaust valve. I know that the ebpv can get clogged but I didn't know if this was what it sounded like.
After a couple minutes it started to idle constant and when I took it for a drive it drove nice and had plenty of power.
Any ideas on that idle tone change?