Anyone recognise this behaviour? When it's really REALLY wet, my S-type 2.7 turns into a bloody Austin Seven - the firtst turbo simply gives up boosting altogether, and I find myself changing down, and down, and down, to get up steep motorway hills or even try to overtake anybody. Fuel economy is crap, too - all the way down to 31 on my last long soaking wet trip.

When the weather improves and the car dries out - while driving along! - the boost slowly comes back. Not quite as good as I remember it from just after the remap, but the hundred-league boots feeling definitely returns and the economy improves back to the levels I've been used to seeing.

I assume this might be just one damp wire, or a wastegate, or similar: My mechanic isn't a Jag specialist, but he is excellent - where should I tell him to start looking?

 

start : tighten all boost hose clamps