If the problems are related, it could be restriced exhaust. This would cause rough/poor running, and possible hard pedal due to lack of vacuum to operate the brake booster. If you could remove the oxygen sensor before the catalytic converter, and run it, you may see the symptoms gone. If so, the catalytic converter needs replaced. Another way to condemn it is with a backpressure gauge, anything over 3 psi indicates restriction.
Sunday, August 15th, 2010 AT 2:29 PM