Ethanol... I see that corrosion all the time, ethanol blends allow the gas to carry MUCH MUCH more water, it rusts out pumps just like what you're seeing. That's where all the corrosion came from, the metal of the pump.

As for replacement pumps, if that one is working then just run it till it dies but there's some good threads floating around about installing aftermarket pumps like Walbro. Mostly this was for the V35 platform but I don't think much has changed on the pumps, probably more threads around for the V36 but these were the ones I referenced in the past. If you use a larger pump you WILL need to do the swirl valve and regulator modification like shown in the second link. That's exactly what I'm running, a 255lph Walbro in my 2006.

https://g35driver.com/forums/engine-...ation-diy.html

http://www.christurnbull.com/project...-g35-fx35-etc/

 

just wanted to give a quick update. was tinkering with the car last week and threw torque obd app on it to check the afr. it started leaning out to around high 13s low 14s at wot again (the junk yard pump from last year was getting weak). got lucky and scored a new hitachi unit from ebay for $100 and tossed that in. it's now back to hitting low-mid 11s at wot and high load again. i couldn't really tell a difference when driving it, but it did develop a random slight rpm dip (like it's about to die) during takeoffs (in 1st gear) and had a strange start-up hesitation after leaving it sit for about an hour.

highly recommend testing your afr @wot if your stock pump is getting up there in mileage. like i said, i couldn't really tell a difference when revving it out, but running that lean at high load can't be that great for the engine. Apparently, our ecu didn't have a problem with that...