300TDI Auto Oscillating throttle

[Cleggy]

My Discovery 300tdi auto has just developed a fault which causes the revs to constantly vary up and down whilst travelling at a constant speed. Other symptoms are a lack of power and a max speed of only 60mph.
Could it be caused by the clutch being on the way out or possibly a faulty throttle sensor? Has anyone experienced anything similar?

[Jon v8]

Welcome to the forum,what model year is your Disco ? If it's 96 on then it will have Bosch EDC,a fly by wire system and will need to go on testbook to see whats going on.Pre 96 it will be a Bosch VE pump with mechanical governing so needs "mechanical" diagnosis.
Before you panic too much though,either system will give similar faults to yours if they are not well fed with clean,air free diesel. So check for possible leaks,blocked filters etc.Remember that until the lift pump the fuel is under suction so will tend to pull air in rather than leak diesel out.A favourite on tdi's is a rusted/cracked pipe coming out of the top of the fuel tank.
Also check that the engine is being fed an unrestricted flow of air - no blockages or delaminated intercooler hoses.
Be dark by the time you checked that lot !!!!!!!

[Cleggy]

Hi Jon,
Yhanks for the reply, that should keep me busy. I forgot to mention that the motor seems fine in neutral anf the problems only seem to be present whilst driving. Would this discount any of the possible fault suggested?
Cheers,
Cleggy

[Cleggy]

Problem solved -The bottom hose had become disconnected from the intercooler. Thanks for the pointers.
Cleggy