Over the past 2 months, I've needed to have my car jump started to get the car going. Very odd. I have a 2 year old battery that my dealership says is good and that I looked at also to be good.

The only issue in the last little while is that sometimes my check engine light goes on when I'm stopped at an intersection. Once I accelerate, the light goes away.

I've left the car at overnight at airports for 3-4 days at a time and been able to start the car again. I checked the terminals, the alternator is good. No error codes.

Shop says nothing is wrong. All I know is that I have jumper cables in my trunk now and 3 strangers have used their random cars to jump start a Jag in the last few months.

A month or so ago, my power windows didn't work properly on the one-touch windows up. Going down the windows would one-touch down, but that's no longer an issue now either.

WHAT'S WRONG??? Need some insight or user experience if possible...

 

FYI

2002 X-Type 3.0 AWD Sport
around 130,000kms now

major issues in its lifetime were...
some gearbox issues that led to rebuilding the transmission around 100,000kms, new fuel rail back around 30-40kms in its earlier days...

 

If the car starts every time you connect up jumper cables yet won't start on its own battery, then you are looking at either a bad battery, the connections to the battery are bad, or the battery cables themselves are bad (most likely the negative as most people connect the positive jumper cable to the battery and the ground wire to the block of the engine). Since you have cleaned the terminals already, I would be leaning towards a bad battery cable (negative most likely based on what you are describing).

If you want some checks to make to confirm a bad cable, let me know. Just need a multimeter to do this check.