Corsa Idle and power loss?

I have a 2001 opel/vauxhaul Corsa GSi 1.6

In the last week I've been driving quite a bit in peak traffic and the weather has been nice and hot. In the past two days my car started idling sporadically and have developed a 'flat spot' while accelerating...it feels sluggish as well

I suspect it might have something to do with the air flow meter but I'm not sure. Could it maybe be that car is running to hot? It has anti-freeze in the cooling water and new oil.