Hi, I'm hoping someone can help me with this. I have read through previous threads where people had similar problems, but my situation is just a little bit different. I have a 2010 G37 base sedan and have 2 problems:

1. The fuel gauge appears to be overstating the fuel amount by 1/4. A while back I ran out of gas even though the gauge showed 1/4. Since then I've noticed that when I fill up, the gauge shows as full but it stays full for about 100 km of driving and then it starts to go down. After that, it seems to go down in a normal way, corresponding to the amount of kms driven. I generally fill up when it hits 1/2 tank which I believe is actually 1/4 tank of actual gas.

2. The check engine light is on but it's flagging the MAP sensor. I actually replaced the MAP sensor a year ago so I'm surprised that it went down again. The check engine light does not indicate a problem with the fuel gauge.

I'm aware that it could be the fuel sending unit(s) or it could be the gas guage on the instrument panel. I don't know if there's any relationship between the two problems though and am trying to avoid spending money on a fix that doesn't work.

Any help would be appreciated.
Thanks