2004 V6 70,000 mi. Tonight I drove 30 + miles for shopping. Vehicle was warmed for 10 - 15 min before highway speeds. After 30 mi arrived where I was going and it sounded like I just traded for a V10 TDI. Guessed it was starved for oil but at max. Definately sounds like top end noise. Added some engine additive no luck. Any ideas ? Sound is pretty constant idle - 1600 RPM then tappers to nothing. Driving me and the car next to me nuts! If it were a GM V motor I would say it was a collasped lifter noise. This can't be the case here. Thankx.