OK, so where does it go???

Like anything good, it went to the Tax Dpt :))

Wouldn't happen to be an 80 series with the factory steel wheels would it?
They commonly get circumfrential (sp) cracks in them which causes this sort of theing to occur.
If so you need to get new wheels, not safe to weld them or fit tubes as the rims will eventually let go.

It's a mystery, ain't it? Our '93 80 series doesn't lose any air but the wife's new Kia Rio seems to have lost a few psi evey time I check it!

Always thought there were a lot of oxygen thieves out there.

Did you put it away after checking pressures hot.

Be aware that alloys can and do lose air due to porosity, shouldn't be a problem these days but was a big problem in the past. We had a Rangie with alloys that had the problem and the tyres had to be taken off, the rims 'painted' and the tyres refitted before they would hold air.
Occasionally you can get porous tyres too, usually fixed by coating the inside of the tyre with a special sealer.
not likely to happen on the Jag but grit and dirt in the bead can also cause slow leaks on tyres, i've had it happen on the camper especially after a bit of off road work involving mud and dirt.
If you suspect the rims get a tyre place to loosen them, tyre soap the bead and refit as a first step as this is the most likely spot, if it still happens get the tyre place to inflate to max pressure and immerse in the test tank, watch for bubbles.

From the Cooper Pedy News
"Air pressure should always be checked when the tyres are cold before temperature can affect them. Tyres can lose up to 1 PSI per month due to air escaping through the rubber as it stretches.”

Hmm....

PSI thieving seems to be on the increase.

No wonder at the recent State election a promise of 800 more police officers to exert law and order was popular.

Maybe they will form a special police branch to combat PSI thieves.

Our taxpayer dollars are at work!!!!!

I used to have this problem but I now regularly take my vehicle into the tyre specialist and get the air in the tyres rotated. Works a treat.

My theory is that by giving the air regular rests in the spare tyre it doesn't feel overworked and is thus less incclined to leave home.