My 2013 G37 with 128,000 miles suddenly has been running and idling very rough. It's perfectly fine when I start it and go when the engine is cold, but when the car has been running for awhile and I'm driving, then have to stop and get out for a few minutes, and drive it again, it idles very rough and stalls out.

When this happens, I have to wait about 45 minutes or so until I can drive it again, and then it is usually fine.

The "Service Engine Soon" light came on, and my code scanner read the following three DTCs:

1. P0301 - Cylinder 1 misfire detected
   
2. P0300 - Random / multiple misfire detected
   
3. P0174 - System too lean, bank 2
   

I can schedule with a mechanic to fix the problems, or I'd like to see if it MIGHT be something I can do myself?

Any ideas on what's going on?

Thanks in advance!