Disco 1 300tdi idle issues

Hi guys,

Got a P reg 300tdi disco manual, over the last few week it's been idling from anywhere between normal (700ish) to 1100rpm, now it was bothering me but with working lots I kind of got used to it and thought I'd fix it when I had some time off, but yesterday I fired it up from cold and it idled fine then the revs built up on there own to about 1750rpm over the course of about 2minutes without me touching the pedal. It also as an inch or so a slack in the throttle pedal now which suggests the cable is jammed but I just can't figure out when starting it will idle at normal rpm then build itself up! I've tried running it until it got hot and the problem still persists so am a little stumped.

Any help will be much appreciated thanks!

Just thought I'd say there is no power loss and it also starts first turn as it should no issues there what so ever

Thanks again

Could it be running on it's own oil? Take off the air intake to the manifold and see how oily it is in there. There will be some oil but if it's dripping then I would suspect the turbo may be your issue.