check engine light on, i pulled the codes here is what i have code#177 HEGO system shows always lean (left) and #543 fuel pump secondary circuit failure.what to do?will run fuel pressure test tommorrow if pressure is low replace pump problem fixed? did i answer my own question or could it be something else.but i dont understand just left side showing lean? car runs good and check engine light is not on all the time but when its on sometimes it will turn off when i accelerate hard. all help and info. appreciated, thanks. BILL.