It has been difficult to start my 1990 740 GL with about 112,000. After reading about similar problems on this site, I replaced the flexible air hose from air box to throttle body (old one had a hole in it), the plugs, and the flame trap and applied throttle body cleaner twice. It usually starts better now, but it takes various amounts of cranking to start it, whether the engine is hot or cold. The ignition switch is acting funny--sometimes the engine will start when I move the key slightly to the left during cranking. Can a contact problem in the switch lead to cranking without engine firing?