Hi!..........check for the code yourself, as in the previous post......only takes a few minutes.........then clear the code(s)....and see if it comes back.......i have a '93 also, during the recent cold snap it gave me a code one morning, i checked it, cleared it and it hasn't come back...probably a transient from starting at -25F.........sorry , don't remember the clearing procedure.....something about holding the button in for 5 seconds.......do get the bentley's manual....best $30 or so you'll ever spend on your volvo.......O2 sensors should be around $100.....cheaper if you look around...there are some posts in the archives about sources for cheaper sensors that work just as well...i think one of them was that the b230f engine with LH 2.4 (our '93's)can use the same sensor as the 5.0 liter ford...common engine in ford products........good luck.......j.