I have a volvo 960 wagon that runs rough and stalls on occasion. It used to happen only when it was very cold (-25 ish and below), but is now more frequent. the rough running can be gotten rid of by re-starting the car. When this is going on, it seems to be running rich. The upshod of it seems to the that the plugs get gummed up quickly. When they pull the engine codes, they seem to be variable, anwhere from faulty coils to faulty oxygen sensors, and they seem to vary in which coil has the problem. I had heard that at some point the type of solder in the ignition computer was changed and this may be the problem? Is this actually the case? is the likely problem the ignition computer? what else could it be. oh, its a 1996.