fuel smell

I have a 2010 Buick Enclave with a new engine with 40,000 miles on it. I have a check engine light with an error code of P0304 and a strong smell of fuel with white smoke coming out of the left tail pipe. I believe I have a failed fuel injector. Any other information helps.

I have a 1994 buick roadmaster i have a issue with the horn honking on its own for no reason as well as when i use turn signal dash lughts will flicker and sometimes the speedometer will go up and down with the blinker. I also have issue that the car can take a time or two to get started...