Different companies fuels have different additives in them even between the 95 and 98/99 ron fuels and they don't always mix well

I usually use Optimax and my car loves it but if I run low and can find a Shell and I have to go to a different station my car runs like sh!t for as long as the other fuel is in there, then for a couple more fill ups it miss fires now and then.
Did you go from BP unleaded to Optimax as I find a BP/Shell mix to be the worst of all
