It is possible that it is not supplying enough current. Have the battery loaded tested. Looked for loose connections and a bad ground.

It is possible that the pump is getting a voltage drop causing lean condition ...but it would also show a dropping fuel pressure ..have you monitored the fuel pressure during the run ...if pressure rises and is consistent during boost I would look into tuning or injectors issues ....If you see very little increase in fuel pressure or a drop during boost I would look to mechanical issues ...voltage ..vacuum line ..etc

I have just sent my car back to the workshop yesterday...again.

This time they will put it on the dyno and monitor what the pressure does under load. So will know soon if I have pressure drops.

Found the issue, it was a faulty FPR.

They replaced it and told me it is now holding steady 11.1-11.5 AFR under WOT.

:)

That was an easy fix, diagnosing it not so much.:tup:

That is why I am a huge fan of the mityvac mv5445. It’s the only fuel tester that gives you a 100% outlook of what the fuel system is doing without having to leave your stall. Sadly not many have one and then people chase their tails on what is going on.

Dude, why are you using Australian products?
Lol

Strange, after my boost controller install I am getting a lean spike on the graph of AFR Bank 1 midway through a WOT.

Anyone have this issue before?