A little work today

Today was in the low 30's so I worked on the sound deadening on the Festiva I was only able to get half of the passenger rear floorboard section done as it wasn't quite cold enough for the thicker sections to flake off easily I spent about an hour on a 12"x18" section. I also did some work on the B6T. When I drove the Capri home I noticed that it had a rough idle and would miss under boost until the engine warmed up. I had reservations on what it might be and with all the emissions i feared a long slow trouble shooting process, I knew that for the last 5 years the car only ran 87 octane so I ran the tank to about empty and filled up with premium and saw a smoother idle but still had problems under boost. So being the environmentally friendly person I am I next cut the catalytic converter off held it up to the sun and proclaimed "Well there's your problem". Now now more miss at idle or boost even when cold and this engine sounds mean with only an open downpipe.