The Engine light stayed on (no flashing) after slightly rough start. Dealer says P0300 code which is a misfiring cylinder. He says one or more fuel injectors must be replaced (over $1000 if all 4). He says fuel injectors cannot be cleaned. I had fuel induction cleaning service done there 6 weeks ago due to rough start, ( no engine light). Does this sound right to you? Can fuel injectors not be cleaned? How can I be sure the fuel injectors are causing the misfiring? Any knowledgeable thoughts would be most appreciated. Thank you.