i had a 55 plate Focus Zetec 2.0 tdci that on several occasions suffered from a loss of power when attempting to pull away or accelerate from a crawl. the engine would idle eratically and when trying to rev the engine the rpm would decrease further.

i managed to clear the fault each time by stopping and restarting the engine a few times. when first contacting a Ford dealer i was told they would need to conduct a diagnostic check at cost which i felt was unacceptable under warranty. when the fault returned i contacted a different branch of the same dealer who carried out the diagnostic check free of charge.

the test found that the eGR valve had "frozen" to cause the sudden loss of power. the valve was replaced under warranty and the fault did not return within the next 10 months of ownership until sold.

Sorry to hear of your problems.

Exhaust Gas Recirculation (EGR) valve is, as the other poster has said, the best place to start. This part was problematic on this engine on early Focus II, but is more reliable in later cars. A competent DIYer should be able to get this out and give it a clean as it can get gunked up with soot. An occasional blast at high revs (e.g. hold onto 4th on the Mway for a bit at above 3000rpm for a minute or two) can help blow some of this crud out of the back.

However, I would be very surprised that this was not the first place a Ford dealer looked, as EGR valve problems were relatively common. Might be worth a second opinion from a different dealer. Or try and find a diesel specialist if the problem is not resolved within warranty. However, because the problem has been reported within warranty, but not been resolved to your satisfaction, I would continue to press Ford to resolve the problem.

I think it's very unlikely to be poor fuel quality. I'm assuming that your reference to the M8 means you're in Scotland. I understand that virtually all road fuel in Scotland comes from the Grangemouth refinery (regardless of brand). Supermarket fuel may be less likely to be contaminated as most supermarkets sell so much, that it doesn't sit around getting water etc in it, and as the Tesco fuel contamination debacle of 2007 shows, I doubt you'd be the only person affected.

2- Diagnostic codes: If the main engine light flashes when the problem happens, it means a code is being written to the car's memory. On the Focus II, the codes stored can be read by using this process. Start with the key in, but don't turn it. Hold down the button on the end of the trip computer stalk, then turn the key as far as bringing on the dash lights (e.g. oil, glowplugs etc). Keep holding it, and after a few seconds, it should go into its diagnostic mode. Press the stalk button again, and it will cycle through various diagnostic tests (e.g. dash lights, gauge sweep, data from key sensors). Eventually, it should display codes like P0123, although if none are stored it will just cycle through all the same tests again. You can then check any that have been stored online, or tell the dealer.

Hope that helps. Let us know whether you get to the bottom of the problem.

Hmm interesting, I have a 2006 2.0 tdci Ghia (estate)

I bought it from work a year last december with 75k on the clock. After speaking to the driver he said it had-had a problem with random loses of power (once nearly lost it on an overtake). After lots of diagnostics and checking of the EGR valve it eventually went away when they replaced the vacuum advance unit at 67k miles.

Now the car has been absolutley fine whilst I have had it, except for today. After booting it to overtake a couple of cars on a backroad I settled back down to doing 60ish round a few corners and noticed a little stumble going uphill. Car seemed ok though, slowed down for a little village and on exiting the 30 limit gave it some and ... nothing. It was like treacle had been poured in the engine. No warning lights, nothing. Would not go over 2800 revs and took a long time to get to that, had a bit of tourqe at 1800 revs so at least allowed me to get it through the gears and upto 60. I was only 5 miles from the works yard so nursed it back and after restarting engine as mentioned in above posts it seemed fine again. It now has 92k on it btw.

Coming to think of it I seem to remember the last driver saying it happened on inclines.

Its in for a cambelt change next week though so I shall see if it does it over the weekend. If it does I shall ask them to change the vacuum advance again and will let you know if it fixes it.

Edit: checked the fault codes as mentioned above and did not have any stored.

Edited by Whisky on 30/04/2010 at 15:19

I am having exactly the same problem as you had in 2010. I have owned my 2005 Ford C-max for 2 years, it has done about 75k miles and I regularly get it serviced. About 2 weeks ago I was driving and came off a roundabout when the car suddenly lost power and the car behind me nearly went into the back of me. No engine lights came on and the car would still move but it was as if I was stuck in first gear. I restarted the engine and the problem had gone. I took it to my local garage and they couldn't find anything wrong with it.

The same problem happened again yesterday, I was coming off a slip road at 30 mph when the car lost power and I had to restart the engine again and the problem disappeared.

Did the Ford garage find a solution to your focus?