Intermitent car/spanner symbol on dash?

Hi peoples. Any ideas or experience of this?
Got this intermittent fault on my 2.2 Direct, 06 plate, that pops up, usually if stuck in traffic for ages or after parking for 20 mins ish. Spanner/ car symbol but not the engine one appears, engine will die wont restart, or wont start after a park up of 20 mins or so or runs fine with light on? Is intermittent. When I connect my OBD reader it says no faults found, and yet, if I still clear faults, the light goes out and all is ok for a while. I recently had to replace the evaporative emissions relay as that was doing virtually the same thing, but put the engine management light on and a fault code but now, no fault codes. I am guessing a temperature related issue with something, but can not find codes and am reluctant to pay money to a garage to faff about trying to get this fault to occur in their own time at my cost.
Many thanks in advance.
Pete.
 
Top