Hi guys I've had my S2 for a few weeks now it has had a mis-fire and low revs and on boost, but it broke down the other day, I have got it back so i can start ticking off boxes to get it sorted, pump relay, pump, timing, adjusted the lifters (has soild) etc. I can only grt it to run with the flap held down and it still sounds like it misses when i rev it (don't need to hold the flap once running) the flap does bounce when it sounds like its missing if that makes sense?

Been pulling my hair out so any help would be great