Check engine light and smoke (94)

So I bought this concorde a few weeks ago, it ran fine up until today when I started it up cold and it idled rough and I noticed that the check engine light was on. Oil level was good - no oil indicator came on - the gas gauge is not very accurate so I put 3 gallons in - and I put in some fuel injector cleaner with no results.

I'm not thinking wear and tear b/c it was fine one day and the next it was bad.

please help.