Not an expert, but sounds something like auto choke, auto adv timing, etc. Not.. working correctly. most cars use electronics, so anything in display?, errors etc. will not tell you the error No, just a light on that should not be.
Could be something sticking, Could also be something simple. Have you checked your air filter. (Main stealers did not change mine, when they said they did, screwdriver through instead. (I am lucky to be here)) So check yours if you have not, filter blocked, would give rich mixture, same as if choke was on.
SD, November 2011