Engine adaptations (fuel injector timing/duration, lean/rich mixture settings, spark plug timing, VANOS timing) are always being adjusted to reach optimal performance. They are only ever changed once the O2 sensors are at operating temperature. This takes longer than 25 seconds. They are also slowly adjusted, its not an on/off switch. Resetting them to all 0s doesn't speed up the process. The engine still has to adapt itself either way. Having done dozens of of diagnostic tests involving adaptations, the shortest I ever saw the values start to change was around 15minutes. It still takes 30min to a couple hours for them to fully stabilize.

A little sad to see this post end without a problem to the OP's solution. -Because i'm pretty sure that's what the OP ment.
As I understand it, replacing the spark plugs actually solved a problem with an over-eager accelerator pedal, that has now become a lot more civilized.
White Lancer, am I right?

The thing is, my 2004 4.4i has the exact same issue. I have to be extremely gentle on the accelerator to avoid jumping forward, giving everyone else the impression that I stomped the pedal all the way to the floor.
It can be a little embarrasing sometimes. Not to mention quite dangerous in these snowy conditions.

So allow me to repeat the OP's question: Is there any way at all that replacing the spark plugs -and thereby possibly altering the ignition a tiny bit, can have such a drastic -and in this case positive effect on the accelerator's behaviour?

Fascinating! Maybe I should stop hypermiling.

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