In my experience, which I have explained in two previous posts, I too was getting these spurious mis firing, no throttle response, stalling and the electronic warning light coming on.
I found my problem was the
, despite diagnostics pointing to the
My fix was to remove the
and clean it with carburettor cleaner. A few vigorous blasts with this cleared off all the gunk and residue (there wasn't really THAT much).
As the throttle on these cars is 'fly by wire' this residue causes the throttle flap to stick or hesitate which in turn causes unexpected readings from other sensors in the system and the warning light to come on.
It took two hours of fiddling and a can of cleaner to cure mine. It has been fine for weeks now.
To test for this you could take off the inlet air filter and with the engine running at about 3000 rpm, spray cleaner into the mouth of the intake in short bursts. This will cause the engine to nearly stall. Allow it to come back up to speed and repeat sprays for about 5 or 6 times.
This should improve the running, but will NOT affect a complete cure. It will confirm the probable fault however.