I have a 55 plate 2.5 Auto. on 45000 miles and I have noticed of late that on occasions it can take up to 10 sec or so for the engine to fire up when starting. Normally it will fire within 3 to 4 secs. Does this indicate glow plugs or any other ideas. Car runs fine when started.

in this weather glow plugs will be doing very little, could be a failing engine sensor which in the case of my old Superb diesel led to all kinds of starting problems when hot mainly, but also cold. The sensor could still be providing readings, albeit wrong ones within operating range so the engine light has yet to come on. If you have VCDS, or a member near you with VCDS they should be able to look at what the various sensors think is going on, to try and identify the culprit. My superb had the camshaft position sensor giving out the wrong signals which threw the timing slightly out causing the problem starting.

As above! Crank shaft sensor may well be the culprit.

Sent from my iPhone using klatapaT.

Thanks for your posts - will check readings with vagcom.

Hi, This maybe useful or not, but i've got a 2.5 Tdi 130,000 miles on the clock, last year or so i've sufferred a delay in starting, 5 second churn and then a load of smoke out of the back. The battery failed the other day, refitted the battery with an uprated bosch and all my starting issues, smoke and a few other problems have all gone.