Diesel Mk3 Juddering At 2000 Revs

[Mark Williams]

I have a 54 reg 2.0TDCI Mondeo and I've noticed in the last week or so it seems to be juddering at about 2000 revs. I even think (although I may have pressed the clutch/break) that it casued the cruise control to switch off as happens when you break or press the clutch.

It's not a major problem - doesn't happen all the time but I don't know if it's something to be concerned about? It had a new EGR valve recently - could it be related?

[jeebowhite]

It could be related, but if the engine labours, then the cruise switches off (safety functionality).

It could be clutch, DMF or as simple as a dirty sensor.

ARe you able to run diagnostics at all?

[Mark Williams]

Well scrap the egr valve thought I wad getting mixed up-it was my wife's car that had that.

So not sure why it's juddering. The mpg is dropping too which I guess is related.

How would I do a diagnostic check?

[jeebowhite]

I believe your car still has an EGR valve so it should still be a consideration.

To access the trip computer diagnostics (including error codes) turn ignition off, press and hold "reset" button on the stalk, and turn ignition on, hold the key for up to 5 seconds, and the trip computer should say "TEST" let go of the reset key. now just press the reset button to cycle through to the next menu until you get to DTC - make a note of any codes that come up and let us know.

[jeebowhite]

if you have a code reader or trip computer, you should be able to access the error codes.

Your car I believe has an EGR valve, so it could still be related. Its always worth removing and cleaning it if you have the time.

with the trip computer, turn ignition off, press and hold the RESET button and turn ignition on, hold the RESET button until the word TEST appears on screen. Then, click RESET button over and over till you get to the DTC menu, make a note of all codes if any that are shown.

[Mark Williams]

Thanks - I'll give that a try. To check, by the reset button do you mean the one next to the mileometer that I use to reset the trip mileage?

[Mark Williams]

Also, once I've been through and found any codes, do I have to cylce through all the different checks (by pressing the reset button) or can I just switch the ignition off once I've found the codes?

[jeebowhite]

If you have the trip computer (i.e. the stalk above the stereo keys next to the steering wheel) then yes, however if you only have the mileage reset on the face of the instrument cluster you cannot do self diagnostics, and would need to buy a code reader.

Have a look at my signature for further information and a link to a guide I did on buying a code reader :)

[Mark Williams]

I have a trip computer so know what you mean now. I'll try it this afternoon / evening and see what happens. I assume I just switch the engine off after I'm done?

[Mark Williams]

I've just tried it and it says DTC None

[Mark Williams]

Any thoughts on what I can do next?

[jeebowhite]

OK so that indicates there is no critical error codes, but there still could be some (plug in code reader would be required).

Disconnect the MAF sensor and try running the engine, see if it improves.

[Mark Williams]

Thanks for your help with this - much appreciated. Apologies, but when you say the MAF sensor....?