My first post, please forgive me. I did not find any other similar posts dealing with this issue. I have a 2005 G35 Sedan. I replaced/resealed the leaking valve covers 6 months ago. When I put everything back together I screwed up and reversed the #4 and #6 coils. The engine sounded like hell and ran terribly for a mile or two until I took it back home where I searched, found, then corrected the problem. Now it runs smooth but I have the following problems: Engine service light on, determined to be O2 sensors, won't go away even with multiple resets. Burns about a quart of oil between changes. Hard starting most of the time, but once started sounds fine and makes good power. I am afraid that I damaged the valves or something else when I ran it for 5-10 min with the plugs reversed. If so, how bad off am I ? Thanks in advance for any expertise.

 

Ironically I did this myself a couple months ago.

Engine code: is it the P0300 code? bank 2? I have that. Tried many things and gave up. I will be taking it into a specialist to diagnose. Been driving since with no issues.

Oil consumption: normal on these engines sadly. You'll find tons of material on this.

Hard starting: can't help you on this one, sorry.