Exhaust question

[Zman2000]

Hey guys, just purchased a 2000 z28 and someone has removed the cats, I was wondering how many are suppose to be on this car and I see two can shaped pipes right off the stock manifolds are these cats as well?

[raynor139]

The cats came right off the manifold in a stock setup. You should have 2

[Zman2000]

What about the one under the passenger floor, I can tell there was one there, there is a tube welded in now, once I get a crazy idle only skip out of her the exhaust is going to be changed to Texas Speed.

[raynor139]

They replaced or did something there but that's not a location for a cat

[Zman2000]

Strange my 97 SS had a cat there where the raised floor is.

[raynor139]

Yeah on the 98-02 cars it was just a pipe that had been flattened out for clearance.

[Zman2000]

Gotcha, well thanks brother for that info, the LS is new to me, but learning fast, just wish I could nail down my terrible idle in park or when coming to a stop, it shakes the whole car, but when you accelerate or Nader speed runs perfect.

[raynor139]

Guess no codes or anything? Some times at speed you won't notice it. I had an issue with a misfire once where at idle it was there but at speed it was only noticeable at certain rpms. The misfire shook the whole car. Almost felt like it would shake itself apart. Turns out water was in the computer.

[Zman2000]

So how did you find this out and what did you do to fix it?

[Zman2000]

No no codes, weird thing is, I've tried to purposely set codes by unplugging the MAFand the IAC and the ATS. It will not set a code for nothing, the light does work because when I turn the ignition on it lghts up.

[raynor139]

I finally gave up and took it to a mechanic. It took him a few days of troubleshooting to figure out why but it was at least throwing a code at times