Will have a good look under the bonnet tomorrow, but I would guess its on its factory MAF. At 7 years old / 94k I would say its wise to replace it anyway as the elements get full of muck. I might well stick a new one on it anyway as they are not expensive.

My other thought is the throttle body, will have a look at that tomorrow too.

Well spent the whole day changing the brakes. All friction components now brand new to OE spec. Not made a jot of difference.

Sigh.

I spoke to the chap who did the recon gearbox on the car, which is still under warranty, so I am going to get the car to him to let him have a look. I hope he knows whats wrong.

Been told to try a gearbox flush...

Gearbox oil as it came out

Click image to enlarge

Just an update this issue is still ongoing.

Still spending hours reading up on this! Now started on X5 forums!

My latest "fix" is the chance it could be a blocked cat.

ODBII reader coming tomorrow....

 Range Rover Vogue 4.4 (2003)

Well, still got this problem even after changing the O2 sensors.

To update so far I have done the following:

PCV - checked. Hoeses are replaced and all ok. *
Gearbox double flush done. Made no difference - maybe shifts a bit smoother though.
New spark plugs. Old ones looked grubby - but made no difference.

The car is showing no codes.

*I am going to take the PCV valve off now and just check to see if its ok or looks blocked.

Any more ideas chaps?!

To add - I have noticed the car also does this when stationary....!!!

I hope this is going to be a big clue to someone.

So, you start the car, hold the throttle very lightly at about 1000rpm and after a few seconds the revs start to drop and fall even with the throttle pressed exactly the same.

I tried pulling the maf connector and it does the same thing. No change. If I plug the maf back in the car stalls.

Could it be the maf?

I really hope someone can help as so far I have just been chucking money at this thing like there is no tomorrow and I really have to stop spending money on parts that dont really need changing...

 Range Rover Vogue 4.4 (2003)

New video.



Car is in park.

Started car, press throttle light and hold at about 1000rpm. Revs start to rise and fall on their own (as they do when driving on light load).

Then, after a few seconds I increase revs slowly and the "hunt" goes away as I press the throttle a bit more.

I then reduce the throttle back to light load and it starts to hunt again.

In the last moment I let off the throttle and it settles back to idle again and all is fine.

 Range Rover Vogue 4.4 (2003)

Just to add some more detail to this. I just let the car cool off to cold.
Tried again. Did not do it in cold start.

Once warm after a couple of mins it did start doing it.

So, what is the sensor that is _NOT_ used in cold start?!

Anyone!?  Range Rover Vogue 4.4 (2003)

Does this engine have a CTS (coolant temperature sensor) Earlier Rover/Range Rovers had them and they could cause hunting and over fuelling problems, they were less than £15 to replace. It would be worth checking if this engine has one fitted and if so change it

I think so, its part of the thermostat housing isnt it? Range Rover Vogue 4.4 (2003)

It's not the coolant temperature sender unit, that is a different item which sends the temperature back to the temp gauge on the dash.

The CTS collects info on temperature and sends it to the ecu which then adjusts the mixture.

As I say I have no idea whether these engines have them but I know for certain the EFI Classics and the P38 were fitted with them

Um, not sure TBH. Will have to do some digging.. Range Rover Vogue 4.4 (2003)

My first thought are throttle pot worn.. though I'm not sure if its fly by wire or cable though strongly suspect it would have a pot.

Second thought which should come first is stop trying to guess. Take it in to someone with the CORRECT diagnostic equipment for your Range Rover and see which sensors or readouts cycle at the same pattern as the revs are doing. Then go from there. 2010 Disco XS TDV6, 2009 Freelander 2 GS

Previous Landrover products -1990 110 TDI CSW, 2003 TD6 Vogue - RRC TD Vogue, RRC v8 Fleetline, Disco ES V8 LPG, 101 Ambulance "Morph", 1964 SIIa Auto Powered by Jag 4.2 Lump - "Percy".

Probably not relevant to the RR, but my 3200 Maserati did this, it was a combo of the throttle pedal potentiometer and the throttle body feedback pots. Mind you although it was drive by wire, they had mechanical feelers on resistive strips that wore through causing limp home mode and erratic idle. I'd guess the RR uses digital hall sensors not mechanical ones. 2006 Mercedes CLS
1991 Retro-style Mini
But really finding it hard to fight the urge for a S/C...

Hi my car (2002 range rover 4.4 HSE ) has just started to do this and very annoying it is. I serviced it about a month ago including radiator flush and gearbox oil change. It is exactly the same fault as described by the Op. I have a Hawkeye diagnostics and it shows no engine or gearbox faults. Did you manage to cure it?

Mick

Why not go back to basics, start with fuls and air ? Is it getting the same contnuiouse amonts of both ? Could it be being starved by one or the other or getting surges of one or the ther ?