Car Keep Cutting Out When I Push Brake

[taylor89]

Hi please help

I have a R reg ford fiesta with a 1.25 zetec s engine and I have recently changed it to a 1.4 zetec s and now and again the brake will go hard and wont stop me but when I push it the car cuts out and got to start it back up again, this have happened twice before and after messing around with bits and jumping on the brake pedal it start working again but it happened again last night on me I can't get it to work again I've tried everything that I use to do to make it work. I've asked around and people have said clean the idle air control which I have done. someone said it might have something to do with my ECU which I didn't change when I fitted new engine.

thanks Scott

[taylor89]

car cuts out on low revs

[jeebowhite]

Could well be an ecu issue but also the you saying as soon as the brakes seize up the car cuts out?

[wase16ll]

could be a servo issue, if servo is failing/leaking air, brake pedal will go hard, takes real pressure to apply brakes....plus the air leak will cause the engine to stall...

with engine running check for air leaks/hissing around servo unit/ hose coming from servo and inlet manifold