My 2005 Pilot EXL has 95K miles on it, newer tires and is overall very well maintained and in great shape. Recently, I've noticed a noise on the highway when I'm running 70-80 MPH on newly paved highway lanes. Usually, there's so much road noise that's all I hear, but if I switch to a newly paved lanes the road noise goes away and it sounds like the exhaust from a semi tractor in front of me, but it isn't from a semi, it's coming from my car. If I gun the accelerator the engine noise revs up (and sounds fine), but the noise I'm trying to locate doesn't change. If I switch back over to the lane with older pavement, the road noise drowns out the unexplained sound.

Is something causing buffeting - again, it sounds like diesel exhaust from a semi (pop, pop, pop). The noise is very rhythmic and doesn’t seem to change with speed changes. Like I said, I thought it was a semi in front of me on the highway. No vibration in the steering wheel, like I said, tires are new. It sounds like it's coming from the front end / under the hood.

Thanks in advance!