Running Rough, Intermittently

Running Rough, Intermittently

>I need some help with a problem I'm having with my 86 928s
>with automatic transmission 67k on it. The engine runs excellent
>at times and then out of no where can run very rough, almost like
>a few cylinders drop out. Then, after a little while, it will clear up
>and run excellent again. I just replaced plugs and wires with no

Replace both coils.

Response to Reply:
I would like to thank Dave Roberts for diagnosing a problem with my 86 928S that has plagued me for the past couple of years!! He answered a post that I put on this site that Porsche mechanics themselves said" was a bad fuel injection brain to the car needs fuel injection work". I found this site one day and I've learned a lot about a car that I had lost interest in!! All you guys/gals that are on here and help people every day are just great!! I now have a car that is running excellent and by the way also looks excellent ( I never lost interest in taking care of the car, kept it under a cover in my garage and still cleaned it even though it didn't run very well ). Well back to Dave, with a very simple description of what kind of problems I was having he told me to replace my two coils. Well guess what problem solved!! Now you can't get me out of the car!! BAWAAAH!! Man is it quick!! Any gatherings happening soon in the Northern Virginia area or any where close? I am willing to drive!! Once again thanks Dave!! I owe you one, please send me info on your RMB that every one always talks about. With the money you saved me on repairs I can easily afford one and buying some thing from you really makes me feel good!!

Thanks Again!!

Al Fontane
86 928S A/T Prussian Blue Metallic

A new coil worked for me too. The car had run rough for a few years and I couldn't track it down until finally it wouldn't start. The spark was very weak. It turned out that the wrong Bosch blue coil was fitted.
The correct one should have a resistance across the primary (low voltage side) of 0.3 ohms. Mine turned out to be 3.6 ohms. The part number I had was for 4cyl VW's and not the correct one for a 928.

79 928 5 sp

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