I've had a noise for awhile now that sounds like a vacuum leak but can only be heard with a load on the engine at around 2000-2300 rpm's. I have replaced EVERY vacuum hose and even all the evap hoses and solenoids and electrical switches (partly as a PM measure but also to try and find the issue). Well yesterday I believe I found the issue, I had my car up on a lift and noticed that when I replaced the distributor cap with an MSD cap the cap to isolator seal dropped out of position and the lower portion is hanging out the bottom of the cap. I can't repair it right away but just wondering if it would be a good idea to cap off the opti vent vacuum source at the intake for now and just leave the fresh air vent line connected? I should be able to get it repaired properly in a few weeks.