More problems... yay

[kimmykun]

Hey, all.

My car's engine been making a weird fluttering sound lately. I have no idea where exactly it's coming from, but it comes and goes.

It's been getting really shaky in trafic lights. If I put the car in neutral, the shaking subsides, however.

And just now, my car wouldn't stay on until it heated up a little. Same flutter sound right before it died.

Anyone have any idea what it is?

I have a '93 base V6.

[Money pit Beretta]

Can you find out where the sound is (front,back,or side of engine). Do you have the check engine light on when it's running? Is the RPM going up and down? Is the sound a hiss or is it more like a knock?

[rweatherford]

Plugged up cat converter which is causing a leaky exhaust at the flex coupling.