Engine miss a idle speed on 2005 Ford Taurus

I noticed when I am sitting at idle speed like at a stoplight my engine has a slight stumble in at every now and then.I have new plugs,wires,air and fuel filter.I put some lucas injector cleaner in but it still does it.Any ideas.Thanks

1 answer 2 comments
SCAN CODES AND ADV ON CODE
I had a code pulled and it was 0300 random misfire multiple cylinders
you need to have this diag by your mech could be a mulititude of things