MAF problem

[Nate29]

Ok im having a maf problem with my red top sr.I come to this conclusion cus it won't go past 3k when driving but it will when in netural.not throwing a code 4 it but i tested it and the power wire is reading 12v and the signal wire is reading 1v and what iv read its spose to be 5v.but iv switched out mafs with a buddys and it still was doing the same thing.So my question is is it bad wiring somewhere down the line or is maf bad.thanks for any help.

[Z-tune!]

it's possible it's the wiring, but unlikely unless you recently did something new to it. are you sure your friends maf was working? did you test the voltage with that one? did you try blowing on it and making sure its using the full 0-5v range? have you done anything new to the motor around that same time?