2005 Nissan Path:replaced batt, alt, plugs, coils due to rough run & smoke. 1st smoke was blue after new parts it's more gray or white. New plugs smell like fuel. Exhaust is rich in fuel smell. Ideas?

Blue/grey smoke is typically engine oil burning.

Grey/black smoke is typically excess fuel (or insufficient air).

White smoke is invariably water that has turned to steam. (water is a natural product of combustion as well as the stuff the head gasket keeps out of the cylinder).
Sometimes an engine can emit a fine mist of unburned fuel that seems like white smoke.

Clearly your engine is burning some engine oil. Perhaps the valve stem oil seals are failing. When an engine noticably burns oil it must be realised this isn't good for the oxygen sensor and catalytic converter and it is inevitable the life of these things will be shortened.

It is doubtful the replacements you have so far carried out will have changed anything and it is likely to be coincidence the colour of the smoke has changed.

What is needed is a diagnostic check to inspect the live data from the sensors when it will probably be found one or both oxygen sensors will need replacing and perhaps other things have grown tired too - at an extended mileage an injector could start dribbling or the spray patterns be so poor the engine won't be able to burn it all and then it will be expelled into the exhaust.