Engine will crank but not fire when I turn the key the first time, but starts right up on second try. Started doing this after I replaced camshaft sensor on passenger side (US model). Then bought an OEM camshaft sensor and still doing same....

 

Can you check for fault codes as that might suggest something relevant? If a cam sensor code appears you could probably swap the two sides over and see if the fault moves.

It sounds like something to do with the immobiliser/key transponder system which, hopefully, will show up on a scan.

Richard

 

I would also check the fuel pressure.

You might try and 'cycle' the key a few times to energize the pump before cranking the starter.

 

Yeah, I was thinking fuel pressure too. Difficult to see how the sensor change would be related, rather than coincidental.