[JFP in PA]

Originally Posted by RoadsideStig

I don't think its the ECU nor the MAF. The CEL is flashing i'm worried it could be something major like a cracked head but then I think my car has 565XX Miles?

First, you need to get the car scanned on a Porsche specific system (PST II/PIWIS/Durametric), as some generic OBDII unit give erroneous results.

Second, any of the Porsche systems can look at air/fuel ratios, individual injectors, etc. to eliminate them. Third, if you think there is a serious mechanical issue with cylinder 5, get that cylinder leak down tested (you could have a dying or dead valve spring, etc.).