I have a '93 960 wagon with 186,000 miles which has been running fine. I just had it on a recent 300 mile road trip and after I got back home the engine started running rough. I changed the plugs, but the roughness was unchanged (old plugs looked ready for a change but normal).

I checked each ignition coil module using a spark tester and found that #2 was not firing at all (#5 is a little weak but all other cylinders have a normal spark.)
I checked the resistance of the ignition coil and it seemed normal and also swapped in a coil module from an operating cylinder (which gave the same results).

I now want to check the wiring and the power module -- but it appears that #2 is controlled by the power module on the firewall side of the intake manifold and I don't see any easy way to get at this. Has anyone done this before? What is the best way to get at this power module? Any other troubleshooting recommendations?

Thanks in advance,

Jon