Recently my m42 has developed a surging idle issue it will just sit and bounce within a few hundred RPMs. I replaced all the vacuum lines not too long ago, so it's not a leak, and the car runs fine once you are on the gas, and never stalls out idling, just surges. The only research online yields it might be a clogged ICV but seems like every person that pulls it out to clean it, has issues afterwards too. Any ideas?