When my 95 S420 is warm, it cranks 5 to 10 seconds before it starts. When it's cold, it starts a bit easier -- but it never starts instantly like it did before a few months ago.
Also, at the same time it began smelling like it has an incomplete combustion issue.

Replaced plugs, dist rotor (caps looked ok) and O2 sensor to no avail.

95K Miles.

Any ideas?