At 2500-3000 rpm, my 2.8 has the exhaust note of an old VW beetle. It sounds as if the car has an out-of-tune carb. When I give it more gas, the sound goes away.

I was thinking exhaust leak, but I've checked the length of the exhaust system and found nothing.

There's no ticking from the manifolds when I open the hood.

I'm wondering if there is some kind of fuel problem. Bad pump, FPR, or injectors.

Also, how do I control the throttle from the engine bay? I believe the system is all electronic and there's no cable.