a weird one here my car is missfiring but only when the brakes are on. it tries stalling if sat still on the brakes like it traffic lights. any ideas? ? cheers

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www.icswretail.co.uk

I would give the idle control valve a clean, see if that sorts it, thats what cures it alot of the time. If not, check vacuum hoses, could be a leak or a split, if after that no change, see about getting another idle control vavle and see if that works

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done all of the above, the only weird thing is tht it's only when brakes are on otherwise it idles fine, :S idle valves a bit noisy though very clean cuz its always in petrol

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www.icswretail.co.uk

I would say that definately sounds like a vacuum leak.

As that's the only real way the brakes can affect the idle by making the engine work harder to keep the vacuum up.

The ISCV should compensate for this though, so you may have both faulty. Would definately recommend a new ISCV though as its cheaper than a master cylinder, which if you can't find a leaking hose is the next likely culprit!!

Paul

not as good as the fiat pick up i was in friday night, when you braked the right indicator came on

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dont fiestas have a vacuum assist on the servo for the brakes ?

If its happening when the brakes are on it would point to that..... more than likely the end where it attaches to the servo