2000 GMC Sierra

"brian" <worldindustries DeleteThis @shaw.ca> wrote in message
news:QEhki.99549$1i1.91635@pd7urf3no...
> My friend has a 2000 GMC Sierra 1500. The exhaust is our problem, he has
> headers and Magnaflow exhaust. The Y pipe and the cats are our problem.
> Their are O2 Sensors before and after the cats. I was wondering if we
> could cut the cats out and weld in pipe the same diameter of the rest of
> the exhaust and not have problems, with trouble codes and such, or do we
> need to get high flow cats?

There is no need to remove the cats, or spend money on "hi flow" cats, if
your factory cats are still good. The factory cats flow extremely well and
have some extra flow capacity, so even if you have done some work on the
intake or internal mods to the engine, you should be good to go.
However, if you do remove the cats, you will have a problem with the rear O2
sensors throwing codes. Also, if you are in a state that has inspections,
it will be a hefty fine for tampering with the emissions devices.
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