hi my 2004 focus, every now and then the speedo goes down to zero and looses power, any ideas

Speedo sensor for sure.

VSS (Vehicle Speed Sensor) as clive stays, its basically fitted onto the gearbox and picks up the speed the road wheels are travelling then sends it onto the ECU.

You will need to pick a new one up and get it installed.

Thanks for the reply guys is it easy to fit a new one. Apparently the clip is a pain and access is not easy

not having personally changed one, I hear it can be fiddly, but can be done my someone with a bit of confidence and a lot of patience!

It is generally a git of a job although some do get lucky.

Buy a sensor and pin off ebay and find an independent garage that will do the job.

http://pages.ebay.com/link/?nav=item.view&id=371020090906&alt=web

Put a new sensor on yesterday thanks for everyone's help

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Any problems fitting it or did you let a garage do the job?

I got one off eBay, the pin came out easy, it was a pain removing the sensor I got a pair of pliers with a long piece of wire and wiggled it and pulled on the wire and then it came out no problem, it was a pain getting the pin back in lining up the hole on the gearbox' there is a post on YouTube I watched that and went for it, I have scratched my arms and hands doing it but I'm pleased that I got it done in the end

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You are a true Ford fan now ;)

Problem resolved though?

Every thing seems ok so far fingers crossed

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By the symptoms I am 100% sure it was the sensor.

The power loss is a dead give away.

I can't see you having any further problems.

Hi all, I have experienced a similar problem. I have a focus lx 2005. I will be driving along and the engine system fault light will come on (red explamation mark in red circle cog) and when I change gear I lose power and then it gains speed again. I have to pull over and turn the engine on and off. Then It goes off. Sometimes it stays on when I turn the key over and the light stays on. If the light stays on the engine won't start. When it does this... I bang on the dash above the speedo and the light goes off... Please help!!!!

You can try the dashtrick but that probably wont give you much, it sounds like you have a serious sensor issue, could be camshaft.

Have you got access to a code reader?