I've got a friend with a 96 Volvo 850 non Turbo. His car has recently developed a problem with the engine’s ignition system. We have checked the wires and plugs which to be in good working condition. We then went on and suspect that the ignition coil might have gone bad and replaced it with an original Volvo ignition coil. The problem still exists. Does anyone have the similar problem or tips on how to go on and diagnose the problem? Thanks.