Regarding the engine, ( and any other faults ), one of the first things to do
is to check to see if there are DTC's ( Diagnostic Trouble Codes ) stored in the ECU.
Many of the codes are ERASED from the Memory after 3 "No Fault" starts,
so for intermittemt faults it is often the case that the relevant code
will have been erased by the time you visit the Dealer

Fortunately it is very easy to see any codes that have been stored,
by displaying them on your instrument panel

This Link will direct you to instructions on how to do that :
Servicing Data, Reference Info. & DTC ( Fault ) CodesAt the bottom of the most recent post you will find a downloadable Word Document
that has a list of all the DTC's, and a description of their meaning.
Make a note of any stored Codes ( and look up their meaning ) so you can inform your Dealer
in case they have been erased when you get there !

Cheers

