[tomc88]

my mechanic is coming tomorrow. Will let you know what he finds...

"P0304 fault code is a 'generic' misfire code for number 4 cylinder and I would be surprised if that is the only code as a misfire on one cylinder would not normally stop the engine running.

We know of a few instances on our customers' cars where the engine oil separator, (internet acronym AOS), has failed and allowed engine oil to be drawn into the induction system. This can be the cause of the smoke emission, although the one instance on a Boxster 2.5, did cause subsequent total engine failure! (It cracked the cylinder, but the 3.2 and 2.7 engines have stronger cylinders). There are though other possible causes.

The best course of action is your suggestion of us coming to you to read all fault codes, and depending upon the results, maybe gaining access to the engine and attempting to rotate it manually. A possible further check could be to disconnect the pipe between the oil separator and induction manifold to check for excessive oil."