Hi, I have a 2004 g35 coupe I recently bought and the service engine light came on for about 1.5-2 weeks. Today it went off but I finally had some time to take it in to a mechanic and he check it out for me. He said the code P1166 came up. Can someone help tell me what this is?

 

Probably an bad O2 sensor or an exhaust leak.

Read this: http://www.370z-uk.net/forum/viewtopic.php?f=10&t=14145

 

Is this a pretty easy/cheap fix?

 

I think my service light was on because of this and now it is off. I think the previous owner was using octane less than premium and I let my dad borrow the car for a few days and he put in regular in when using it, I only put premium in it. Do you think this could have been the problem?