I should provide a little background to this issue as I believe the two are most likely related.

The car is a Ford Focus 2008 1.6 TDCi Diesel (UK) which this year has had a brand new battery and alternator.

Most recently I got the error code P242F stating that the diesel particulate filter was blocked with an ash accumulation. I have been able to resolve this issue by blanking the EGR valve this past Saturday (19th Dec) and everything has been working well since, or so I thought...

The issue:

This morning on the way to work I was driving down a straight and narrow country road at around 40mph when I suddenly found that pressing the accelerator was providing no power to the engine. A few moments later the battery and oil lights came on and the engine cut out so I drifted to a stop at the side of the road. I was immediately able to restart the car and tentatively drove the rest of the way to work.

After some investigation I can confirm the following:

  • The car doesn't stutter/judder or anything when it cuts out, in fact the first time I couldn't even tell it cut out.
  • No error codes stored in the ECU.
  • Battery and oil lights are a red herring, they will always illuminate if the engine automatically shuts down due to low revs.
  • Engine must be at or over 3000 RPM in any gear, as long as I stay below this then the issue does not occur.
  • The engine must be warm, the error doesn't seem to occur when it's cold but I'm not 100% on this.
  • If I press the clutch I can restart the engine immediately and carry on driving every time.
  • I can't get this issue to occur when stationary, only when driving. This may be to do with the engine being warmed, but I had idled for some time before trying this to make sure it was warm.

I'm a complete novice with cars but I'm pretty good at following instructions so after some research these are the things I was going to look at (in order) and wondered if anyone had some advice.

  1. I have looked for any cracked or loose hoses but can't see/hear anything.
  2. As part of fixing the DPF issue I removed and cleaned both the EGR and MAF first. I'm wondering if I haven't formed a good seal when replacing the MAF. I'm going to remove it and check the seals before replacing it again.
  3. I don't recall the fuel filter being changed in the last 2 years so I'll replace that for new.
  4. I've heard that the Throttle Position Sensor is a common cause and since they're roughly £20 I'll replace for new.

After that I'm out of ideas for things I can try myself. I'm looking to trade the car back into the dealership I bought it from early next year so I'm not spending a fortune replacing parts as it's not worth it.

  • 1
    Changing the fuel filter sounds like a good place to start, it could be fuel starvation. – HandyHowie Dec 23 '15 at 22:38

In this case replacing the fuel filter for new seems to have done the trick. I was able to find one for roughly £27 on eBay and fitted it myself in under 45 minutes. Thought I'd leave the information here in case anyone else has the same issue.

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