About a week ago the car lost all its power on a 93 z-28 camaro. The exhaust went quiet also. I have ran out of options in my head that it could be except the cat. I had the opti-spark replaced in July and I also noticed a good bit of oil coming from what appears to be behind the water pump. I was wondering if the idiot that replaced the opti, didn't change the seal where the water pump goes into the engine, if that could be the oil leaking. The main problem is what the heck would cause that much loss of power and the exhaust to go quiet like a new car sounds. Plus while you are accelerating you can hear sorta this hissing sound from under the car. I am clueless so I am asking for help to see if anyone ran into the same problem.

 

Does the engine have problems revving?

It sounds like exhaust blockage to me, but there's always the possibiliity that something else is acting up... but you might as well go down there and see if you can locate the hissing.

 

not sure....but im gonna guess the cat. had to have mine done for what sounds like the same symptoms your having. mine will be ready tomorrow.
didnt get the buick after all...

 

you can get on it but it doesn't sound like it is going to eat you alive like it normally does, even though it is running like crap I showed a kid in a honda "rice burner" what a real car is. Beat him and then did my victory 3 doughnuts and left him. Keep in mind the car had NO horse power right now so that was pretty bad on his part

Back to the reply, yes you can put it in neutral and rev it, and it is still sluggish.

 

I had exaxtly the same problem. The cat. was the problem. Material inside the cat. was broken into chunks and plugging exhaust flow. I dropped the Y pipe and cat., used a long punch and broke up the material into small pieces and cleaned out the cat. The exhaust sounds great and exhaust back pressure is reduced. My car runs great again.

 

I really appreciate all of you guys help. I assumed it was the cat, but I didn't want to happen what usually happens from the assumptions. I guess now to break the heck outa some ceramic baffles

 

That was it!!! A big fat piece of the ceramic baffle jammed right in the middle of the cat outlet. LOL most of it was gone, so I guess it went out of the tail pipe. It is amazing what some pressure will do to a cat when the optispark melts and causes the car to backfire Oh well that is fixed now to fix the oil leak from where the dude didn't replace the seal for the waterpump main drive shaft when he fixed the opti.

Thanks again!!!!!