Originally Posted by Jeff@topgearsolutions
Could be a tiny vac leak? That is really the only other thing if everything is that new and perfectly installed. But like I said, this car had a poor idle always, some worse then others.
My last car had that shutter you speak of, but it was because I had over sized injectors from the blower and nitrous i was running. A little tuning fixed that though. It's usually fuel related when you get that random shudder.
forgot to Mention all the vacuum line were changed from the waste gate actuators all the way to the brake booster haha
but your right it might be tune related. time to hit up terry!