Clogged cat?
Racer
Joined: Jun 2006
Posts: 408
Likes: 0
From: Elkton MD
Clogged cat
Yes, a clogged (or broken) cat could cause sputter. More often there's a very large reduction in high rpm power from a defective cat. Occasionally (in severe cases) there will be reduction in intake vacuum at high engine loads (accel or hill climbing).
Sometimes a broken cat's pieces will bounce around producing intermittent problems (or lack of problems). If yours are bad, take the opportunity to look thru the cat and compare to a new one. And knock some of the insides out and look how it's made. Imagine some of those pieces turned sideways so the tiny ducts are sideways to exhaust flow; they won't pass much exhaust.
Leaky valves also cause exhaust sputter. We used to hold a playing card against the tail pipe to check for smoothness and pop-back. Lots of popping usually meant poor valve closing.
Hope this helps
Sometimes a broken cat's pieces will bounce around producing intermittent problems (or lack of problems). If yours are bad, take the opportunity to look thru the cat and compare to a new one. And knock some of the insides out and look how it's made. Imagine some of those pieces turned sideways so the tiny ducts are sideways to exhaust flow; they won't pass much exhaust.
Leaky valves also cause exhaust sputter. We used to hold a playing card against the tail pipe to check for smoothness and pop-back. Lots of popping usually meant poor valve closing.
Hope this helps
Thread Starter
Racer
Joined: Jul 2004
Posts: 389
Likes: 2
From: Howard Beach, NY
Originally Posted by CREWZIN
On my 87, the CAT broke up into pieces and came out the rear and got caught at the "Y" junction of the tailpipe. Couldn't get any high revs till we diagnosed the blockage.
Thread Starter
Racer
Joined: Jul 2004
Posts: 389
Likes: 2
From: Howard Beach, NY
Originally Posted by RRT vette
Time to take the cat off and inspect.
I'm guessing this is a 84-91 since you stated cat and not cats.
I'm guessing this is a 84-91 since you stated cat and not cats.
