You need three things for each cylinder to produce power, fuel and air, spark, and compression, and they must be equal for all cylinders. If compression is low on one cylinder, that will cause it to develop low power and you could feel that as a misfire, but typically you'll have a fuel or spark problem causing the misfire. The Engine Computer on '96 and newer cars can set fault codes telling which cylinder is misfiring. Once that is known, if simple parts replacement doesn't solve the problem, the mechanic will often switch injectors between two cylinders to see if the misfire goes to a different cylinder. On a lot of newer cars that can be done with individual ignition coils too.
Thursday, June 28th, 2012 AT 8:45 AM