my gtu is running lean on the rear rotor, I notticed this two days ago when I changed my spark plugs, the two trailing are both white (very lean) and the 1st leading is perfect but the 2nd leading is white too. I dont know how to adjust this, I thought that the computer would do this by itself. please give me some feedback on this.

 

you may simply have a partially clogged injecto or something else causing a lack of fuel flow to the rear rotor. Because, yes, you're right the computer knows how much fuel to put in and that doesn't change unless you have a piggy back.

Now would be a good time to pull the manifolds and have a look at the injectors.

But do you have a pic of the plugs?

 

The computer is not adaptive for fueling.