Flashing check engine light!!! Help!

Today was a first... a flashing orange check engine light! Has any one else come across this? and if so... any ideas what might be wrong?! The car is a ME7 T5, it still drive normally, returning usual mpg and ticks over o.k. However, the christmas lights come on when it comes under heavy load (i.e. you put your foot down) in any gear. Once the power starts to come in the engine power seems to drop off rapidly as if the STC was doing its thing. It also has a similar feel to the STC operating, a kind of heavy vibration - the ecu limiting the power i guess. Let off and then it stops (doing odd things) and drives normally again. The check engine light flashes for about 10-15 seconds if the car is under load and doing odd things for more than around 3 seconds. I've had a look around under the bonnet but cannot see anything broken off fallen off. I will connect up to the laptop tonight and pull off the codes. O yeah, it does it with STC switched on or off. No previous problems like this that I know off Any thoughts very welcome!!!

mrdave, A flashing check engine lamp is an indication of a missfire , have the codes read and repaired before it causes catalytic convertor damage. Mister T.

Just read the codes with my trusty little reader. P0305, missfire at number 5. Looking around the net the common thing seems to be either the coil pack or the plug. Any thoughts? Will get the spanners out later and have a poke!