Hi all, I have an '06 F-150, 6 cyl. 55K miles. Started running rough last couple of days, hesitant on accel, I even had a couple of backfires, engine light on. Came up w/ a combo of codes p0171- system lean bank 1 and and P0316 - misfire on startup. Coil and battery both check out good. It's been recommended I start with giving the injectors a good cleaning. 55k seems a little too soon for new plugs or wires, or am I wrong? Any ideas helpful. thanks.