Land Rover Repair: 98 landrover discovery, land rover discovery, throttle position sensor

Question
98 land rover discovery
V8 4.0l
Gas / Automatic

John, here is the problem. i have just purchased a discovery and there are a few things i just cant figure out how to fix. i'm usualy really good at fixing cars. the back windows will not go down while using the front switch panel  or the back switches. secondly, when driving (accelerating)when passing 40km/h the car will rev and then switch gears with out further depressing the pedel. i dont know if that is a tranny computer problem and how it can be resolved. it will switch gears easily when the RPM is over 2100 while passing 40Km/h. when using the selector it with switch gears fine in 1st,2nd,3rd but in D it will rev. any thoughts on this? i know this is alot to ask but it is my first land rover and i just want to make sure that it is in perfect condition.

Answer
Hi Bram,

the window switch problem is very common with LR's. Sometimes its the central switch that needs replacing, sometimes its the window motor and sometimes its the security ecu that is the root of the problem.  You may consider bench testing the window motors to make sure they work.  One owner was so upset with LR (Lucas) wiring that he rewired the motor and switch to by-pass the central switch completely.  IF its a security ecu problem, I would suggest you have a LR mechanic perform the repair.

As for the high rev, it could be the throttle position sensor.  I had this problem and it too seems to be a common problem.  It may not necessarily be a tranny problem.  As the TPS continues to fail, the revs will get worse.  New TPS installed by dealer is about $500 to $600.

Best of luck,

JohnMc

NB:  send me an email and let me know which city you live in.  I'll try to find a local LR mechanic close to your location.

Also:  www.car-part.com is a great source for salvaged parts.  It will save you loads of $$$$ when doing repairs.