>>>>> When the throttle is just moved of idle both sensor indicate the system going lean as opposed to what i would expect a richening .There is also a wide flat spot on stabbing the throttle this feels like a faulty MAF ,any ideas please <<<<<<<<
MAF ???? Possibly, most likely, definitely. err well possibly and most likely anyway.
They are a common failures on Yaris. and are another one on our stock list. ( We have only been able to scource from main dealer so far, but the same part also fits other Toyota's and even fits X Type jags.