I have a 85 190e that idles at 1300rpm. i have tried everything that I have seen here on the forum to fix it. The only things that i havent fixed is there isnt a check valve in my power booster vacum line ,and there is a relay misssing in my fuse box (the one that is in the bottom right side) I think its for overcharging. Can either of these things cause it to idle high?