I've had my '02 LS for a few weeks now, I've changed the timing belt and water pump as well as the idlers and cam seals. Love the car, Recently took it on a long road trip, and I've noticed that the car is louder than I had expected. Runs just fine and I was able to average 25-26mpg's on the highway, 17ish mpg around town. It's not obnoxious or anything, just wondering what the engine/exhaust should sound like at idle? It's got a nice, low rumbly sound you can hear from inside and outside the car. Sounds like it's got a V8, I was just under the impression these cars were more quiet? Am I wrong? I've driven a few LS460's and my 430 is significantly louder. My independent mechanic suggested doing spark plugs. No tapping or anything to signify an exhaust leak, just wanting to make sure I've got a healthy engine. Any advice would be greatly appreciated.

 

I can't hear but can barely feel the car idling while sitting inside the 01UL. I can hear the engine components turning when standing outside next to the engine bay but can't hear the exhaust.

 

I can't tell the engine is running when inside. No noise or vibration. Standing next to the engine area, makes almost no noise. No exhaust sound at idle. The only time these cars make noise is under hard acceleration. Sounds like you've got an exhaust leak or aftermarket mufflers.