I was diagnosing a service engine light and when I took it for a test drive I pegged the peddle. After a few seconds of good power I suddenly lost power, heard a loud rattling sound and saw a cloud of brown in the mirror.

Car idles fine and the loosing power problem seems to get worst the harder I push the car. Under normal driving conditions it seems to run ok and idles fine. Also, I noticed the boost gauge really goes hard over to the red line when it looses power.

The Service engine light problem is solved after I cleaned the egr valve and has not come back. I also replaced the plug wires.

sounds like a plugged cat, sometimes you can see them getting red hot when they get plugged, sometimes they rattle if you lightly tap with a hammer

The spike in boost pressure could be a result of increased back pressure caused by a blocked cat. A blocked cat could also give you the rattle and smoke you describe. I think Justin is pointing you down the right path.

I don't think the cat is plugged, I think it just exploded. You should fix it quick, and plan on muffler(*) as well. Please avoid flogging until this is fixed.

Too bad it didn't explode as I could tell for sure it was bad. I do notice if I drive it easy it does't seem too bad but as soon as I push it a bit, it goes over the edge and the power loss happens with less push on the peddle. The exhaust noise also changes some and it it sounds a bit louder and deeper.

Tapping with a hammer I don't hear a real obvious sound but there is a small amount of something that sounds like a light rattle.

Not sure what Randall is referring to for your cat exploding, but I still think the issue is a plugged cat.

Yes, muffler shop confirms it is a plugged cat. He did not have a universal model to fit on it but had a aftermarket cat that included the long pipe all the way back to the mufflers for 898. But, he said if I found a cat he would put it on for $100.

I see a magnaflow on Rockauto for $122. Anyone know if this is a good fit?

Its always nice to know what the problem is. That often is the biggest part of fixing your car.

I trust Rockauto. If it does not fit, they will replace it, no questions asked. The main concern is whether or not the cat will set trouble codes, and I am pretty sure Danthurs uses magnaflows with no problems. I think you are okay with magnaflow from Rock Auto.

Don't forget your old cat has value. Offer the muffler shop $50 and he can keep the old cat.

if its a muffler shop they should be able to make what ever parts needed to adapt to the aftermarket cat.

dont know what the 50 is about. tell him its your cat and you want to keep it and take it to the recyclers and get the money for it.

When I say exploded, I believe the honeycomb just broke apart. The other concern is when the honeycomb breaks apart, it will get caught in the mufflers if the pieces are small enough.