'92 960...

Last May when we were heading to Portland our 960 had a bit of a hiccup. After filling it at one stop it started to miss. At first it seemed like a bit of a mis-fire but then it got worse and eventually was acting like it was missing on 3 of the 6 cylinders it has. Not only did it seem like it was missing on 3, it seemed like 3 consecutive. The whole car would rock back and forth. It was nasty. Apparently the was black smoke and flames spitting out the tailpipe too. The flames part is relatively important as it points to an ignition problem, not a fuel problem. Anyhow, this went on for a few minutes and then went away...quite abruptly. For the next 400km it ran like a dream. However, after the next fuel stop it did exactly the same thing...and then abruptly stopped again. For entire rest of the week and the entire trip home it ran without so much as a hiccup.

Fast forward a month or two and my wife comes home one day saying the car was doing its thing again. Then again and again. I decided it was time to give something a try so I replaced all the coils and spark plugs. That cleared everything up and the ran ran flawlessly...until yesterday. It acted up for about 1/2 hour and then quit abruptly, just like before. Again today it did it, not once, but twice.

So...some input? I've got a set of coil control modules that will go in this weekend. Anything else might cause this behaviour? How about a bad knock sensor? If the computer was seeing horrible knock would it pull enough timing out to make it start missing? It gets gradually worse. It does not start out missing on 3. FWIW, the control modules control 3 consecutive firings in the firing order. Seems a bit silly to me to do that but the engineers that designed it have a little more knowledge about this stuff than I do so who am I to question? If one module goes bad, it'll miss on 3, fire on 3 etc. Makes for a pretty crazy idle and absolutely no power...

I put one coil module in today (I figure if I replace both, I'll have to toss both old ones out as I won't know which one was the bad one). Now we wait...

Thanks in advance,




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Dale