Don't understand why?
 

Well here is something really wierd......

I have always had a problem with my X5 in that the accelerator was very sensitive - any slight pressure and the truck would take off like a 500lb black bear with a finger poked up his arse!

At the weekend I decided to replace all my spark plugs. I opted for the OEM NGK platimun spark plugs and replaced all six.

now the accelerator problem has totally dissapeared? :dunno:

I have to push the accelerator down maybe an inch or more before the truck even starts to move, then the acceleration is very smooth?

I did not do anything else to the truck - can this possibly be related? :dunno:

It's possible your plugs were pretty fouled up and causing slight misfires off throttle, causing a hesitation of some sort. how many miles on the X and how did the old plugs look?

Your eml will probably need to re-adapt to the new condition.

The X has 85000 miles on it.

I'm no expert but the old plugs looked ok to me. The platinum electrode looked tarnished and the earth electrodes looked kind of a rusty brown colour. There was no blackness or oil or deposits etc as I have seen on other plugs removed from other cars. There were no errors or missfires etc, I just decided I would change the plugs as I don't think they have ever been changed.

Try to reset the adaptation .

What is the adaptation?

How do I reset it?

Why would I want to reset it?

Turn the key to position 2 and step on the gas paddle for about 10s then let go turn the key off and start the car and drive you will feel the different.

Driving for an hour or two should get the adaptations where they need to be also.

Would love to try this. Read the other thread saying it takes 25 seconds. Is 10s long enough to reset? Would anything go wrong with it? for example hard to start, engine misfire etc?

That procedure sounds more like ATC (adaptive transmission control) is being "tricked" into initiating the adaptive sport mode...the one that is based on driver influence.

The driver influenced adaptations are based on throttle/accelerator pedal thrust & rate. At every start up...ATC will select 1 of 3 modes based on how the driver is using the accelerator pedal:

1. extreme economy (granny-toe mode)
2. economy
3. sport

In the scenario presented...performing this "test"...only engages the "adaptive sport mode". When the ignition is put into KL 15 (ignition position 2)...all electronics are on. Thus, a quick push of the accelerator to the floor (especially if the kick-down switch is engaged) for a sustained period tells ATC that the driver's style is agressive. Since the ignition is NOT turned off and the car is started...the movment of the accelerator pedal is not forgotten...so the car remains in adaptive sport mode.

This engagement of the adaptive sport mode all becomes moot if the driver's style is NOT aggressive and their driving style is either normal...or conservative...ATC will soon chose the economy or extreme economy (granny-toe) modes....based on how the driver is mashing the gas pedal.

Here's proof of how that procedure is a "temporary" trick: (take note of the text inside the red box that states that driving program selections aren't stored):