Sluggish performance

I have a 2000LS that I purchased when the car had around 32K miles. It now has roughly 147K miles. One of the main reasons I purchased the car was the outstanding performance.

Lately however, the performance (and gas mileage) is nowhere near where it should be. In fact, I recently drove a rental with the 3.4 liter engine and felt like that car would blow my 3.8L away.

The engine feels like it cannot "breathe". I have a K&N filter installed, and it is clean.

There are no codes being thrown, plugs and wires are fairly new, and all maintenance is up to date.

Does this sound like a clogged catalytic convertor? Is there any way I can tell if it is the convertor?

Thanks for any input.

Plugged cats don't always throw codes. A mechanic can do a backpressure test for about $80 and tell if it is the cat. The early Impalas had an issue with the cat material breaking off and plugging them up. GM warranted it, but I think for only 80K miles.

Thanks for the input.

I'll have them check it out.

if you never changed the o2 sensors it is very possible the cats are restricted. this usually results in a slow loss of power and economy make sure you replace the o2 sensors when you change the cat......

I actually have never changed the O2 sensor. I'll check that.

There are 2 O2 sensors. One upstream of the cat, that controls the fuel mixture, and one downstream of the cat, that tells the computer whether the cat is working properly or not.