Is this a Catalytic Converter problem
 

this might sound a little dumb but, about a week ago a new noise showed up in my 99 blazer. its either restriction in air filter assembly sound or it pressure sound possible restricted Catalytic Converters, blazer is sluggish the noise is more noticeable under acceleration and I have engine ping or cam rattle.

if it the catalytic converters on a 4.3 v6 what is the best way / route to go on replacing them on the cheap side. 3 or 4 years and I will pass this vehicle on down the road (maybe). From looking underneath I see the o2 sensors and what looks like two small converters that Y together into a larger converter. I hope in the last 13 years they have come up with a better system. I am not looking for High Output, this is my everyday driver.

The cheapest way is to just get a universal off ebay and weld or clamp it in. There are some hi flow cheapos on ebay for about 50 bucks, just use some spark plug non foulers for the downstream o2 sensor so you don't get a CEL.
Does the cat rattle, give off rotten egg smell or glow when its hot at night? If so, its probably dead. You can also remove an upstream sensor and run around the block to see if its better. It will be loud but it removes some backpressure that a clogged cat would cause.

Or you can try to rent a tester that screws into the o2 sensor and check to see if its clogged.

no rattle nor rotten egg smell have not seen any glowing but I don't drive at night due to vision.

any idea what they call it, so I don't feel like a moron asking about one?

exhaust back pressure gauge. remove o2 sensor before cat, install gauge, start and rev engine to 2000 rpm. if it exceeds more then 1.25psi, remove tester and reinstall o2 sensor and do the same for the sensor after the cat. If the next test reads less then or equal to 1.25 psi, converter is clogged and needs to be replaced.

I well check it out and see if our local place rents one.

Thanks

No problem, let us know how it goes.

I took a trip out to the club over the weekend about 28 miles away, just to see if the convert would get hot or smell funny. No glowing, no funny sulfur smell.