Hi all, I have an 08 G35 sedan (HR) and have a CAI/Exhaust/HFC and went to an Uprev tuner here to get the car dyno tuned. Anyhow, long story short, the car would always lean out when the RPM's go above 6K no matter what the tuner commanded for the AFR targets at that RPM range. Lower than 6K it's fine and made a good 15whp bump down low and it's not even fully tuned yet. Above 6K the AFR just slowly goes up till the 7.5K redline where it goes all the way from about 13:1 to 15:1. The tuner said it was a typical trend for a failing fuel pump. Has this happened to anyone before? Is it really a fuel pump issue? The tuner recommended I install a walbro fuel pump and continue tuning from there. Any help here appreciated. BTW, this guy knows his stuff so it's not a tuner issue.

Thanks.