My 2006 Nissan Titan makes an odd sound, like a grinder, mostly when travelling steady at 35, 40 or 45 miles per hour. Even 1-2 mile per hour difference will cause the noise to stop.

The noise will go away if I accelerate slightly or slow down by letting off the gas. I've noticed that it will also make the same sound around 20 miles an hour, sometimes when turning, sometimes not. It will not make the sounds during steady acceleration passing through 45 miles an hour.

Could this be a wheel bearing, or possibly the fuel pump? It's a difficult sound to locate whether I'm a passenger or driving, as I have a custom exhaust that's rather loud.

Thanks for the ideas!