Odd Behaviour - Is It Clutch??

[Bogbreath]

Hi,

Driving home from up north tonight, got 20 mins in to the journey and noticed the speedo was erraticly jumping around, from 0 to 140 Mph!! Also noticed that the car felt as though I was blipping the throttle as well. When under load, accelerating the speedo was steady and response was good, however when coasting or backing of the erratic behaviour would return. We stopped for half way, pulled up handbrake on and the speedo was still jumping up to 40mph.

Last August whilst on holiday I had to reverse th Van up a hill in a very damp field, I had a lot of smoke from the clutch so am aware I used a lot of its life then. The car is a 2001 (Y) 2.0Hdi (110bhp) with 152,000 miles. Typically I've just had both front springs done!

Any Ideas suggestions welcome!!

MTIA

M.

[steve_earwig]

I can't see that being the clutch somehow, maybe the speed sender on the back of the gearbox. I think that has some kind of say in the engine management too but I'm not sure how much. Or it could be the ecu...

[mjb]

If the diff speed sensor (located at the very back of the gearbox) sends back a varying voltage then it could be duff and causing the ECU to interpret as massively varying speeds, which I *THINK* would cause it to use a different part of the mapping (the thing you get 're-mapped') which could cause the juddering as it changes fuelling amounts. If the speed sensor sends back a square wave, I doubt it could be buggered enough to send back noise fast enough to record 140+mph, although a frayed wire might do it. Certainly an option though...

Other than that I'm stumped if the juddering and speedo issues started occurring at the same time

It could be the ECU, but faults there are rare

Don't take my word for it, this is all just a guess!