Hi all, this is my first post, i have looked around but apologies if i'm duplicating info.

My wife's car is a Fiesta Finesse, 2004 with 1242cc engine.

We are having bother with it cutting out. If the car is up around 3000rpm and you put your foot firmly on the brake, the rev counter goes all the way down to 0. Sometimes the car stalls, other times it sort of sorts itself out: the counter bounces back up to around 1100rpm and then it stabilises. I've had the car into the garage a few times and they reckon it's a speed sensor which is included in one of the ABS units. They're pretty busy right now, so as the car is mainly drive-able they've asked me to return next week so that they can further diagnose the problem.

I'm just wondering if there's anything I can do to move this forward, such as whether I can determine which unit the problem is in but I don't know where to start, either how I find the sensor itself or how to determine if it is faulty.

Is there any advice anyone could give me on this? I'd love to just get this sorted out - it's driving me mad!

Many thanks in advance, Ken

Guys, just to add to this. I have checked out a few places and it seems that there is either one central speed sensor or it is included in the ABS units. I've checked youtube etc. - can anyone even just tell me where to find these and how to check them - it seems from various places I've looked that you can check the resistance across a couple of the terminals... does this sound right? Thanks in advance.