Sitting at a rather long red light this morning i notice my truck start to idle rough. Look in the rearview and notice greyish white smoke puffin out the tailpipe. Put the truck in neutral and idle picks up and smoking stops. Put back in drive and idle roughs up a bit and starts to smoke. Take off at green and everything seems fine. It has only done this one other time about 3 weeks ago. Its a 03 with 32k on the clock and always use FPPF at every fill up. Fuel filter was changed about 2k ago. ANY ideas as to what in the world is going on? I hope its not injectors.