[s-cars] smoke at idle

[Ronald Whiton]

S-folk,
 After idling for about 60 secs. my 95 emits a nice plume of smoke for a
couple seconds then it's gone.
If I blip the throttle while stopped, there is no smoke. I recently tracked
down and replaced a bad coil which cured about 95% of my WOT stumbling
issues, but the smoke remains. Is this a tell-tale sign of any sort? Things
to check?
 TIA
Ron (spy-hunter) Whiton