Ok ever since I've had my car (only 3 months ago), its been clicking loudly at idle or low low speeds. Its a steady click sound that goes each time the engine fires. Also, my service engine soon light came on yesterday.. could it be related? Can I pull codes from a Service light?

 

Check the FAQ for pulling codes. I'd check the codes first. Clicking should be normal (more like a tick tick tick...higher pitch)...they are fuel injectors. I'd run some techron fuel cleaner (12 oz bottle on near full tank), to be on the safe side. The chevron techron is the same stuff they sell in the OEM nissan fuel cleaner bottle (same bottle, different tag).