Blocked cat, or bad gas? It certainly smells like bad gas!

["Sean Ford" <sean@nwh.org>]

Just this past weekend, and through to today, I've noticed the ol' rotten
egg smell eminating from my '92 100 after short trips (less than 10 miles).
I searched the archives and read about the possibility of the catalytic
converter having some type of blockage (which also may explain the rocking
engine idle due to excess back pressure),  so I called my mechanic and
asked him about it. He suggests trying another brand of gas (I'm currently
using Texeco premium, 93 octane), and I'm wondering if anyone has had a
problem with certain brands of gasoline?

Sean Ford
sean@nwh.org
Newton-Wellesley Hospital
Newton, MA  02162 (USA)
'92 Audi 100CS 5spd  17K miles (and counting!)
'89 Suzuki Katana 600 14K miles (and hibernating)