Pontiac Repair: 08 Grand Prix

Question
my car has began making this noise that sounds like vibrating metal with almost an echo sound as it stops.  it only occurs when i accelerate. The sound does not appear to be from the TC but almost like a pulley.  Any ideas?

Answer
Hi Catherine:

well it sounds like it's something belt driven on the front of the engine. Does the A/C still work on this car? If so turn the a/c on and see if the noise goes away if so it's more then likely the clutch on the front of the a/c compressor. if that is the case your better off to replaced the whole assembly then just getting the clutch fixed usually it's just a band air then either the pulley/bub on the compressor goes bad or it starts leaking etc. just replace it if the noise goes away with the a/c on. if it doesn't change it could either be an idler pulley for the bet or the tensioner all pretty common issues on the 3800 engine I'll assume that yours is a V6 engine 95% of them have that engine.... Good luck :-)