300tdi cutting out

I have a 300 tdi (97), recently started running on a veg oil mix.
Past week my disco has cut out on me 3 times whilst driving once while idling. I dont think its related to the fuel as it doesnt splutter, just cuts out straight away, it restarts straight away as well either by bumping as its still rolling along or stopping and turning the ignition, so this is leading me to believe its an electrical fault. Recently had trouble with the immobiliser causing the car not to start however after jiggling the leads in beside the fuse box it started no prob.
Any suggestions, could it be related to the immobiliser?/ the fuel?/ something else?

Hi I tried to run my 300tdi on bio-diesel and it didnt like it, used to cut out at junctions and was harder to start then regular diesel, I would try useing regular diesel and see if the problem goes away.

filters blocked????? mine done the same a long long time ago when i went onto veggie, it wont splutter as theres nothing in there to compress where as a petrol with a fuel starvation will burn what little is in the cylinder, a deisle will just stop dead,
filter and sediment tank!

Further update on this!!!!
This morning after having already done a short trip with no probs i got back into the Disco (was unlocked) and went to turn the ignition and the alarm started going off. locked doors and reopened with the key fob and no probs. Later after stopping went to turn off the ignition the alarm went off again. Has happened about 7-8 times today. Any ideas, is this a common immobilser fault??, this could be the electrical fault causing the car to stop every so often.

immobilsers are known faults with the 300tdi.There is a lead available to take out immobilsers for about £20 on e bay.The unit is on top off the heater matrix box so not the easiest thing to get to.