That's what I figured and why I asked. Blowing air through it will do nothing and is not a test. You need a pressure test to check the cat, and another way is with a vacuum gauge. Read the sticky provided.

 

ok so i am thinking it is the plenum that is bad. (i forgot my haynes book today and am going to order parts online. what all do i need, gaskets, bolts, ect, to change the plenum so i can get those here as soon as possible?

 

Get the plenum plate from ebay. (a member here sells them for less than the hughes plate.)

Get an intake gasket set (fel-pro) from your local auto parts store.

Also:
2 gallons coolant. (not the mixed stuff. Green)
Oil and filter.
Thermostat. (195, unless you have an SCT tune)
bypass hose. (water pump to intake manifold.)
might wanna grab the steel bypass pipe that the heater hose connects to as well.... just in case.
can of seafoam. (for use after you get the plenum done.)
Tune up parts. (plugs, wires, if necessary.... cap and rotor. It just doesn't get any easier than when the intake is out of the way.)
Intake manifold bolts.
blue loc-tite.
permatex gasket sealer. (red or black.)

Might be some details I am missing.... but, that's a pretty complete list.

Optionally.....
Water Pump.
Timing cover gasket set.
double roller timing set....

 

You didn't mention beer.

 

DAMMIT! Figgers I would forget one of THE most important ingredients..... and lets not forget the "friend to share the fun with".

 

You mean, someone to follow the instructions, "Hold my beer and watch this"?

 

That would occur right before you hear the sound of intake manifold bolts breaking.

 

Yea,the plenum is shot, but so is the cat and o2 sensors. Dont just replace the plenum plate/gasket without also doing the something about the cat and new o2's.

 

ok i am going to replace the plenum and gasket. what else should i replace at the same time. gasket wise or other wise.
also if i was to hollow out the cat converter would that mess with my o2 sensors? in Minnesota there is no laws against that

 

If you gut the cat you need to do the non fouler trick with the downstream o2 sensor..