ok so i just got a 03 evo have a few things i would like to find out about it first i have two wires coming off the maf plug that r cut but have nowhere to plug into and they dont go to the maf sensor that and has a code p0138 car has a test pipe and a aem a/f gauge could that cause the lite to keep coming on after code is cleared

 

Maybe a SD tune? then went back to stock hardware. Does the car run? I would find it hard to believe the car would run without the Maf unless it can run in just off of open/closed loop maybe?

 

p0138 code is for the rear 02 sensor, so it is highly possible that the test pipe is setting it off. Either that or it's a faulty sensor.