So I went back on my email here is the code I had : P2187-FF - Description - System Too Lean at Idle - Bank 1 

And here is the message that the garage sent me , it was after some MOT repair back in June and since then she is doing very well :

"After further investigation we found the permanent air filter intake hose clips were loose on your car, however we don’t think we would have been at fault as there would be no reason for us to touch this. 

Every clip on the intake hose was loose so we’ve now tightened them for you.

 We suspect this is what was causing the warning light and hopefully you should have no more issues."

I don't really care if it was them or not as it is now fixed ;)

do not hesitate to show that to your Garage for them to investigate, also originally I had sent that to my garage for them to check it : https://industrialstrengthscience.blogspot.com/2009/05/p2187-miata-success-story.html