I just bought a 2000 lesabre limited with the 3800 in it this January and it has been good to me to far. I did however just put some STP Fuel injector cleaner in it and now it has problems starting.

The thing that gets me is that if it has been sitting for a while it will start without any problem, but if I am running around and turn it off, it will not start up without several cranks and step on the gas pedal a few times. Then of course the whole area reeks of gasoline and black smoke comes out the tail pipe.

Any suggestions as to what I should do?