Two bad things happened at once with my 380SE. First, it started surging, especially at idle. Then, the booster vacuum hose broke. Well guess what cleared up when I replaced the hose today. That's right, the surging. Engine runs nice and even now ... and I can stop on a dime. For those of you having the surging problem, you might want to check the booster hose. It could be the answer for some of you.