power & speedo loss together - intermitant

[Noob]

Hi, I've owned my HDi 100 Exec estate for about 8 years (12 year old car) without any real problems until now and its done 110k miles. The speedo has started to stop working intermittently which on its own could indicate a bad connection somewhere. However the power of the engine drops noticeably at the same time. Its not a major loss of power but is enough to notice and become very annoying. With my limited knowledge I can't think of anything that would cause both of these problems to occur simultaneously. Can anyone shed some light on this problem please?

[steve_earwig]

Hi there, welcome!

What's going on there is the engine ecu also uses road speed to control the engine, so when the speed data drops to zero it assumes the car is stationary and backs off the power accordingly. The transducer is on the back of the gearbox, on top of the differential. You could try cleaning up the connectors & see if that clears it, otherwise the transducer is probably kaput.

[Noob]

Thanks for the help! I'll give that a go.