I have a 2001 Ford Escape that had a cold start ( idle ) problem that I fixed. It turned out to be a lower intake gasket. It has around 100,000 miles on it with no problems. I figured it was time to change the plugs and found out you have to remove the intake manifold to get them. After I replaced the plugs and put it back together the car started having problems idleing when it was cold. When it warmed up to operating temp it ran fine. As it was trying to idle while cold it would idle up and down, almost shaking the car at times. I figured I didn't seal something right so I took the intake manifold off again and put another new set of upper intake gaskets on and put it back together and still same problem. I started searching for a vacumn leak and noticed a leak at the base of the lower intake tubes. I was releasing gas from a propane torch around the intake and when I ran it by the front lower intake the engine reved up. The two lower intake tubes have the fuel injectors attached to them. I pulled up these and replaced the gaskets at the bottom. The car seems to be running fine now. I never even took these lower intake tubes apart originally when I worked on the car but apparently the smallest amount movement must of unseated one of the gaskets. | 
