This could be a range of issues, though some of the most common causes are either sensors, incorrect timing, a fouling spark plug, or spark plug wire. worst case scenario would be a loss of compression in the cylinder.
there could be several causes for Saab9-5 to misfire some are:. Black soot on spark plugs. it needs new catalytic converters. problem in turbo bypass valve or hooter valve. fuel starvation due to blocked fuel filters. uncleaned throttle body. MAF sensor malfunctioning. working of electrical conductors. due to DI malfunctioning
Your card could be mifiring because your spark plug wires could be bad or that your spark plugs could be fouled out which would make your car be missing spark.
misfire is always when there is something wrong with tuning open the hood and take out all the sparking plugs and wash them with gasoline and rub with a piece of ambry paper and place them back