Those 3 letters stand for something big - Intermediate Shaft (IMS). There has been much talk and information about it on the internet, some of it actually true, most just stories by people who have had a bad experience. Here are the nuts and bolts of it. Porsche is no stranger to the IMS. Porsche has been using an IMS for along time. The 547 Carrera engine had one, in fact every 911 ever built has one. In the early engines, the IMS is known as a “layshaft” and does not present issues, even though it had the exact same job as the current IMS in regard to driving the camshafts. The problem is not the IMS but the IMSB (Intermediate Shaft Bearing) in the M96 and M97 engines.