Bug making noise like an electric saw

[batwoman008]

It sounds like a medium electric saw noise when you cut wood, only when I am coasting or right after I take off the clutch or the gas pedal.

My bug has been in the shop multiple times, it has a new belt and new tune up, brakes are fine and they even tried replacing the spark plugs . The only thing they can fine is the catalytic converter had tried to been stolen and some of the beads are loose, they welded up the hole. They also said the muffler is fine so they think its the catalytic converter. Other than that they cant seem to find anything else wrong with it. What do you think? and if so how much would it cost to replace, they said its expensive :/
Also engine light on and water heater light stays on.

It is used 2002 not turbo, manual.

Thanks

[dawildapache]

sounds like a wheel bearing just a thought

[Smileybug]

What codes do you have? Is the temp light red or blue? If its red, have you checked your coolant levels lately?

I would get to an autozone and get the car scanned for the codes throwing the CEL.

[CGK]

It's definitely the catalytic converter.
Welding a hole will not repair it. You need to replace it.
The cat has a honecomb ceramic insert that is fragile enough that if someone poked through it or hammered it, it most likely fractured the ceramic insert and you now have loose sections rattling around in there.
The reason you only hear it when not accelerating is the exhaust back pressure causes the broken ceramic to jostle around inside the canister. When accelerating or driving the positive exhaust pressure forces the pieces to the rear of the canister and keeps them stationary until you lift off the gas.
So, I would recommend replacing it as soon as you can since the exhaust gases can cause the cat to overheat if the flow is impeded or blocked in any way.
Good Luck

[batwoman008]

Ok yeah that would make sense its just driving me crazy and now finally my dad who is deaf in one ear and partial in the other can hear it. Everything else is functioning great.

Do you know how much it costs to replace?