Hey there, I have a 2002 SS with 3.8. I had the same problems you are describing, even the low fuel pressure. The Cat is plugged. The computer has your car in what is called Limp Home Mode to prevent engine damage. GM should have recalled all of these cars. Then GM got in legal trouble over this issue. You should check with your local GM dealer. Your car has only 79000 miles and GM should replace the Cat. for free ! Oh, My computer reset itself after the new Cat. was installed and car running. I hope this helps.

 

I have replaced the cat plus a bunch of other stuff

 

Ok car is now fixed, something to look out for on the plastic gas lines, there is an inner liner of some sort that can curl up inside the outer layer. I did fuel flow test, talked to a service tech at local dealer and told him how long it took to pump a quart and gallon of fuel, they said that there is no set rate but it sounded like I was getting enough, well I was at an idle and if I feathered the gas but not when I wanted to get on it. So after 500.00 in parts and huge headaches, it ended being about fifteen bucks in fittings and new end. Hope this helps someone that has the same problems as I was having. It will pump gas through, but when I tryed to blow air it would not go through.

 

Thanks for the help from everyone!