when you were stuck in the traffic - did you switch off at all and restart? because pretty much all cars will then run a little rough due to heat soak evapourating the fuel.

Otherwise - yes it could be a coil pack breaking down but unless you're unlucky that would normally tend to be one cylinder at a time rather than general misfiring and poor running.

Idle at 1000rpm is too high though - even from cold or soon after, it'll settle below that and eventually sit at around 600-650 rpm at idle (or should do).

I think keep using the car in general driving and see if its a repeat general problem or only happens when car fully warmed up and then stuck for a while in stop start traffic situations.

As mentioned, removing the under bonnet insulation does help a little with heat dissipation.