A brain twister for some, help me diagnose this 986

[Topless]

Inactive Cyl and no CEL error codes? Serious DME problem. A missing cyl should cause a flashing CEL requiring a flatbed ride the the Porsche Dr. Clearing the DME and fresh fuel might be a good start. I want to know A/F ratios, compression and spark advance also.

[JFP in PA]

Originally Posted by Topless

Inactive Cyl and no CEL error codes? Serious DME problem. A missing cyl should cause a flashing CEL requiring a flatbed ride the the Porsche Dr. Clearing the DME and fresh fuel might be a good start. I want to know A/F ratios, compression and spark advance also.

+1, but I would get it properly scanned before resetting the DME to see what it says first..............