Yet again another SES light on 2001 Bonnie
 

I am getting code P0420

possible causes cataltic converter failure.
Engine misfire or running condition
Large Vacuum leak
Engine oil leak into exhaust-valve guide
Piston Rings

What do you all think.

It's been 1 ses after another with this car, but I am determined to get it fixed!

check your vacuum lines with carb cleaner and inspect them thoroghly by hand also spray around the base of the supercharger and fuel injectors and see if the idle changes

where are the vacuum lines located exactly?

Take a look here. https://www.gmforum.com/showthread.p...86#post1390979 This code can come from a exhaust leak. With all the codes your getting I'm starting to think you have leaks. Vacuum and exhaust. Your going to have to go over everything.

https://www.gmforum.com/specifications-general-information-132/vacuum-lines-sensors-278867/

What brand of cataltic converter should I look into getting if that is the problem. aftermarket are about 170 bucks. Is there a certain brand better then another and also the best place to get one.

Unless you hear rattling inside the cat, it's probably OK. Check for a exhaust leak. This includes the exhaust gaskets. If you get a can of seafoam and then suck about 1/3 of that can up threw one of the smaller vacuum lines, then shut the engine off and let it sit for about 20 minutes. Then start the engine. It will smoke a lot. Have a flashlight handy and watch real close for any leaking smoke.

I thought you were also chasing down an O2 sensor issue? Did that ever get replaced?

I'm leaning towards the O2 sensor as well as some vacuum issues.

No I never replaced the o2 sensor yet. I am going to take it back to midas who did the weld job on my exhaust to see if they will warranty it and maybe look for another leak for me.

The guy at midas told me to bring it in and they would do test on the cat coverter and see if it actually bad for free. But he does not recommend using seafoam, but I tend to believe you guys before him. He thinks the P0420 code is my cat converter but I will take it to him today and we will see.