I have a rattle from the front of the car on deceleration. I read that someone had a rattle like this because his wastegate had gone bad. does this sound like it could be my problem?

Make a hook out of a coat hanger. Tug on the actuator rod, it should feel solid. If you can reproduce the same noise you hear during decel it most likley is the problem.

also check the heat covers on the exhaust

I have checked the heat sheilds, but I will try the hanger thing when I get home. thanks.

It could also be your diverter valve. Tt's had lots of problems with dv's rattling on decell or acell. No real way to test it thou.

could be the sign of a bad wastegate or dead cat that has the cells rattling around

Wouldn't the post cat O2 sensor pick up a bad cat? I have pretty much the same problem. Thanks.

well if the cats just starting to go bad then no the post cat 02 wont pick it up right away, if it does you will get a CEL for cat ineffiency

Yeah I'm 97% sure my cats are going bad. The rattling is REALLY bad and the heat shields are fine.

He is what my brother and I did...

With the hood open, turn the throttle plate by hand. Take a metal rod about 1/4 inches in diameter and touch it against the turbo. If the turbo is making the sound, you will clearly hear the sound coming up through the rod. You will need to put your ear up against the rod to hear the sound.

Another method is to use some hose as a makeshift stethoscope. We tried this first, but the hose was made of silicone and it melted.

I referr to the sound as "the rattlesnake." It sounds like some marbles being rattled in a coffee can.