How many miles on your truck, how often do you change your tranny fluid? Do the idle drop as bad when going into drive?
I am wondering if there is a valve hanging up in your trannys valve body.
Mike

 

The car has 260,000km on it. I only bought it last year so I am not too sure of the service history but since when it has been at me, I have serviced it regularly. I have had the transmission serviced last week (another due in a year) and they say there is nothing wrong. Fluid is due for a change at 280,000km.

When going in drive, the idle only drops minimally.

How would I check to see if the valve you're talking about is malfunctioning? Thanks.

P.S. the problem doesn't occur when starting from cold.

 

Couple ideas to consider:
-could be the trans fluid - if you have a lot of high viscosity additives like the Lucas stuff- the stall speed of the converter could be too low
-the new idle valve could be bad or there might be a break in the wiring going to it. Does you idle drop when you turn the A/C on?
-Does the vehicle seems to want to lunge forward/back before it dies? Giving yourself engough room, if you were to shift from park to reverse and let off the brake right away, would the engine still die or would the vehicle start moving?

The valve that DiscoMike is talking about is in the valve body of the transmission -mechanic would need to drain ATF, and pull the pan/filter off. I have heard of ultrasonic cleaning for the valve bodies as a way to fix sticky valves. Don't think that anyone will be able to say for sure by looking at it. However, your trans seems to go into gear right away so this doesn't sound like a sticky valve to me - at idle nothing that happens behind the torque converter should matter because the converter shouldn't be transmitting any power to the transmission at that low of an idle speed.
Piotr

 

Hi Piotr and thanks for your ideas...

It shouldn't be too long till it is due for a transfer fluid change so will do that at that time including a check on sticky valve thing (you're right though, trans goes into gear right away).

Will give the idle stepper and wiring a check however I think everything is ok with it as the idle drops a fraction when I switch on the aircon. Also, the engine isn't stalling any more (after the fixes mentioned in previous posts), just loosing too much revs in reverse and then going back to normal. However, to answer your question, the vehicle does want to lunge forward/backward when put in drive/reverse (I tried as you suggested). I did notice that if I reverse up a slight incline, ease off the gas, and then press slowly again, the engine stalls. Doesn't do this downhill or on a straight road...

 

This may sound like a strange question but how does one clean the throttle body and / or the stepper motor on a 95 Disco?

I have had issue with very low gas mileage, I have changed the cats, gone to a Borla exhaust, changed the air filter box to a open ram type filter (K&N) and it still is awful! This happened when my cats went bad but nothing seems to fix it. I did just change the water pump as I noticed it went bad too (did the pump, radiator, and thermostat) it has about 150K on it. I love my Rover but $$$$

 

I seem to recall that if the purge valve for the evaporative canister is stuck open or the line from the purge valve to the engine is leaking, you will get weird idle symptoms (and if the line is leaking past the purge valve, the computer will throw codes unrelated to the evaporative system). Do you know if any codes are stored? Maybe check the purge valve and hoses? (may try just pinching it off and see if the symptoms improve or get a vacuum guage on it and make sure it's actually doing what it's supposed to)

 

As far as I know the throttle body is cleaned by removing the hose from your air intake to the throttle body. Then, keep the throttle wide open (so that the flap opens up)...spray throttle body (or carb) cleaner into it and brush the metal bits you can reach with a small brush. Once finished with your brushing, spray some more into the throttle body, close the throttle, and start the engine. Switch off and connect hose and you're done. Be careful not to let anything get in the throttle body while cleaning.

As for the stepper motor, I did not clean mine, I changed it at a cost ofAUD200.

 

D2 2003 - I'll check the purge valve as suggested. On Wednesday I am going to get a pressure test done on the transmission to eliminate thatbut I'll check out what you told me before I go ahead with it.