[Scotty_h]

So 've just done this motor swap and inherited a newer Evan Fischer exhaust system on my 200K 3.4 99'. I know the motor I just put in is good, just geared it, but dang, my 300K motor with stock exhaust felt like it had TONS more in the midrange (2000 rpm+)

The only thing I can blame it on is this fart can noise coming from the cats as i go through my power band.

My question after searching, is what kind of parts are these? (i see them for sale at JC Whitney) could this be choking back my power?.. and lastly, do i need to junk all the way to the headers to get this fixed?

Thanks guys,

[t4r4life]

no back pressure, sounds ricer, i would just swap it with a oem replacement and call it good.

[THatfield]

it's Doug Thorley's dumb a-- step brother

[JBurt]

How come you can't run your old stock exhaust? Are they different?

You could try pulling the the o2 sensors one at a time and see if that helps. I guess it's possible the cat is clogged.