So I just got my longtubes installed and loaded up my 93 octane tune on my x4. It had been idle surging a little after I loaded my tune, but I thought it might have been the vac leak I had on my pcv hose. So I got that fixed and it stopped for a few days and now it's back. It's a little odd tho, every time I start it the rpms surge from 1,000 to 500 every few seconds then drop to 300 and occasionally stall the car out. However, when I rev the car a few times or drive around a bit it will idle fine until the next time I start it. So what do you guys think it is? I have read a few threads on other forums that have addressed surging but I haven't seen one that stops after being driven or revved. Could this be related to my tune?