To check the cat just get underneath it when cold and give the punch. It shouldn't rattle. If it is bad it will rattle inside. As far as the o2 sensor, if you cannot remember when it was last replaced and you have owned the car for 60,000 km+ or 45,000 miles, for the price of it...replace it....

Pull your plugs and take a look, if its been miss firing in one of them there will be a glaze finnish with carbon build up.
My plugs and wires were bad and would studder under any boost preasure, fine at high rpm with out boost.

Ichanged my plugs and wires already.. definite improvement in response.. but still hiccups.. hopeing it'* O2 sensor and or cat converter or lack of */C and not cause of engine.. I had low compression on one of the cylinders 110..

As long as compression is within 15% of each other, they are fine. I have never done a compression check on mine so I don't know what a bad compression is off hand.

Well.. I don't have the book to verify.. but I think it'* suppose to be 150 ?? and one of my cylinders are 110.. don't remember what the mechanic said about the other 5.. will ask him again this weekend.

I'm almost positive it isn't the plugs, they're new.. I was running 2 heat ranges colder, but now I'm back to new stock plugs on the stock pulley and still a misfire.. And better yet, I popped the hood today and the supercharger pulley nut backed itself off, fell on the ground (now lost) and chewed up the belt! Luckily the pulley is still on, but I can't drive it until i get a new nut now...

If it is that bad then you might want to check to see what else is coming loose. Could a really bad vacume leak be causing these problems

Definitly could, being a 92 (I just did some repairs on my vacume lines after doing my coupler) it could have bad vacume lines which would screw up alot, not to mention the SC utilizes the vacume as well. Check the vacume distributor post off the intake - those were rotten on mine.

Similar symptoms can also be experienced from an EGR problem. It might be a good idea to remove the EGR valve, thoroughly clean it, and lube the springs and shafts for each solonoid.

Sorry.. don't want to steal post.. but Bill.. I do have a question in regards to EGR cleaning, and verification of operations and such.. here'* my post http://www.bonnevilleclub.com/forum/...ic.php?t=16459