I have been experiencing an intermittent symptom when starting my 1988 190E 2.3. Sometimes the car will not start immediately on the first key turn. It ALWAYS starts perfectly the second turn. 9 out 10 times it seems to happen when the engine is warm. Idle and performance are perfect. I hear what appears to be the starter turning but no firing. Car has a new starter. It's as if a process is being skipped when turning the key. Seems like one can manipulate the severity by how fast one turns the key. Faster worse, slower better. Failing ignition switch?