May need cat?

[dafirebird]

I have a 2002 3.8 Firebird, minor intake mod and Flowmaster cat-back. Getting a super-fine gray/tan powder at the exhaust tips, throwing code for multi-cylinder misfire. Runs fine all day long until you step on it or drive on the freeway, then it shakes and doesn't want to go any faster. A friend of mine suggested it may need a new cat. I dunno...i called an exhaust shop and they tell me that the powder may be fiberglass coming out of the Flowmaster muffler and not the cat. I know it's hard to diagnose something without seeing it...but any idea's??

[3.4grapeofwrath]

Re: May need cat?

All you need is a vacuum gauge to check for a bad cat. Do a search on line there's plenty of info there.

[bigbrian442]

Re: May need cat?

Flowmasters do not have any fiberglass in them.

[dafirebird]

Re: May need cat?

Flowmasters do not have any fiberglass in them.

Correct...i verified this with Flowmaster. I'm taking it into the shop tomorrow (Friday)...wish me luck and hope it doesn't cost too much.

[2.8 Bird]

Re: May need cat?

The honeycomb inside your Cat might have broken off into pieces or it be more related to your injectors.

[dafirebird]

Re: May need cat?

Update...y'all are gonna laugh...it was a coil pack, #3/5. Something i could've easily done myself if i knew what to look for/how to test. Back in the day when i drove pre-90's cars i did a "tune-up" every year...plugs, wires, distributor cap+rotor...etc. I've changed all 3 coils on this car when i bought it 10 years ago with 30,000 rounds on it, now has a lil over 100,000.

I changed the plugs/wires on my winter car ('99 olds cutlass) last fall...had all original with 145,000 rounds.

[dafirebird]

Re: May need cat?

One more note...turns out, i did end up replacing the cat with a Hi-flo Flowmaster cat + crossover+collector; a perfect match to the Flowmaster American Thunder cat-back. Seems that the failed coil pack may have taken out the cat in the process...but what do i know about driving with one bad coil pack? I have never experienced how differently a car runs with one bad coil that feeds two cylinders...now i know. I'm used to cap+rotor ignition...i know how that runs/feels and it's different than coil packs.