I have a Focus MK2 ST 2006 with 43K miles. It has ran with no issues but today while driving noticed a loss of power when accelerating, intermittent 'grunt' from engine.
engine oil pressure and temp all good and no unusual noise.
Fuel was low so filled with premium grade but still same. Also noticed the turbo boost pressure flies up when trying to accelerate hard with little difference in power.
Thought maybe coils or injectors as feels like fuel issue but rapid boost pressure fluctuations threw me.
Idles fine and runs fine if not accelerating hard. Not checked anything yet just wondered if anyone has see this before.
Thanks guys in advance for any help.
meant to say engine is totally standard, no maps or mods.

 

Has the engine light come on when driving?

 

no, nothing at all, drives fine until plant foot, v high boost pressure and no power

 

have you tried being a little more gentle mate? i had the same problem with my ST200 not long back.

was fine when missus drove it but not when i was giving it some stick.

scary when it cuts out after 130 on m6 ill tell you that for nothing


anyway turns out i was just being too harsh, easing onto the throttle made it run sweet as.
to solve my issue i just sold it and bought a cossie. got a heavy foot me lad

cheers darren.

 

......Can you see how much is your afr on full throttle?..maybe too much fuel