Volvo Repair: Misfire, volvo s90, vacuum leak

Question
My Volvo s90, 1998 has a misfire.  My mechanic says it was the transmission so
we changed it, The problem remains. What do i need to do?

Answer
   Keisha, the first thing you need to do is take your car back to the mechanic for a full refund. Have him put your old transmission back in if he has to. Then fire him and find a new shop. How you could possibly mistake a misfire for a transmission problem is beyond my imagination.
   That said, you need a qualified technician to determine if the misfire is caused by a mechanical problem in the engine, a bad injector, a bad coil, spark plug or wire. It could also be a vacuum leak. This not a do it your selfer problem for most people.
   I would scan the vehicle first to see if that sheds any light on it or helps steer you in the right direction.

Mark