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My 2002 Subaru Legacy 250S (2.5L 4 cylinder auto) has a subtle but annoying fault with it's accelerator, which I suspect might be to do with it's electric drive-by-wire throttle system.

When cruising on the open roads under very light load, you can feel a slight on/off sensation right towards the end of the accelerator travel. Sometimes when throttling off, it gives a subtle surging as well.

Sounds minor, but on open road driving it starts to drive me mad. Around town driving you can't notice it. So basically cruising at around 80-100k's, which I tend to do a bit of.

In the past I've asked Subaru "specialist" mechanics to have a look at it during it's regular servicing but I think it's too subtle for them to pick up. Shame really because it drives really well apart from that one annoying fault. The car is well serviced & in top condition, and mechanics have already ruled out any ignition issues or misfiring. To me if feels like an electronic switching "on/off" within the throttle.

Any ideas?

What octane fuel are you running? The recommended fuel for this age Legacy is a minimum of 95 octane.

Has the engine management control unit (computer) been scanned for possible fault codes held in its memory?

Apart from the above we can't say we have come across this problem.

Yes, it's always run on at least 95 octane and according to the dealer the computer shows no fault code. Thanks for the reply, looks like I'll just have to put up with it.