I just got a data logger and after WOT and i let off the gas 0% TPS i get a lean reading of 21.

At WOT the reading is at 10.00

I have a JDM 2001 Evo VII - intercoller, dump pipe, down pipe, three inch exhaust, test pipe and titaium exhaust.

Please advise.

 

What exactly is a "lean reading"? Do you mean knock count? Ignition timing?

 

When you let off the gas it will go lean.. this is normal.

10.00 at WOT (3rd gear) is rich.