Probably a bad injector. I'm the "shade tree mechanic". A guy on YOUTUBE (SKRRRT) had a page that talked about this. Was the smoke white? He said to use Lucas Injector Cleaning once a month to keep your injectors from messing up. Very inexpensive but as far as I'm concerned it works.(Tried uploading a video but the site won’t let me)
Currently trying to diagnose my 2015 v6 F type. Was driving home today and decide to floor it off the line from a light up to 65 mph,the car only went up to around 4K rpm. ,only to have the motor suddenly start dumping a small amount of smoke out the back. As of now the car has,
-quite a bit of trouble starting up
-raw fuel leaking out of the exhaust
-heavy top end knock under driver side valve cover
-idles like hell at start up
The car has 72k on the odm, maintenance has been pretty good throughout its life span,so far my best guesses are a bad injector and a bad egr valve. Thoughts?