Recently bought a 2003 S Type 2.5 V6 and noticed a sort of a miss in the low gears when at low speed. Its coming up as a gearbox fault. I've had a Jaguar mechanic look at it and he can't get to the bottom of it. Is this a common complaint and is it likely to get worse? I can put up with it as it is but if the gearbox is going to die I'll be passing it back to the dealer who has said he will re-imburse.

 

Not sure where you are from but the US never got the small 2.5L so we don't have any experience with it.

You might try the UK S-Type forum?
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Mostly you can treat it as a 3.0 (in USA from 2003+).

Chances are it's an air leak or bad coil. A cheap OBD tool with "live data" such as ELM327 about a fiver on amazon/ebay is a great thing - check only code is P1111 then read LTFTs (see my sig), engine warm, in P, at idle & 2500ish rpm. Post them if you don't know what they mean

Now, it'll likely have the ZF 6HP26 autobox so at least check the 2 bolts on the side of the trans for the shift cable are snug.