My other car, a 1973 145E would start easily enough, idle cold well enough, but when it gets warm it starts to rev up and down up and down. I ve checked for leaks - can't find any. When I disconnect the vacuum line from that thing on the side of the passenger fender it behaves a little better. so I exchanged that part with one I knew was working well and had no success. Go figure that one out. Otherwise the car runs terrific. When in drive the car idles normal, put the car in park or N and it starts all over again, which is another thing I dont get