smart car engine warning light?

[mini_pickup]

ok, so im driving along at around 60 ish and used kickdown for it to drop a gear and overtake up to around 70 when i get a flash on the dashboard of the engine warning light and the engine immediately sounds "lumpy" and looses power, so i pulled over and turned off, had a quick look but nothing obvious. turned the engine back on, and iv still got the light on but power seems to be back. so today im going to check all the spark plugs are clean, the lambda sensor is in nice and tight. but i was wondering if anyone else had any ideas to share with this problem. thank you