check engine light comin on in a 99 xj i know it could be a thousand different things but didnt know if theres anything common that would make it come on that you guys would know about.

replaced a couple fuses the other day checked oil and tranny fluids everything seemed fine

tried to start it today and needed a jump but let it run for a while and it fires right up now.

 

Could have a weak battery - just a guess since you stated you had to jump it.

Outside of that you're right, it could be about a thousand different things. I'm not sure if the XJs are this way, but even leaving your gas cap a click too loose on certain vehicles can set off your dummy light.

 

They'll print you out a list. Just work that list.

 

sounds like what ocasionally happens to mine. My 96' will give me a code i think 12 which means the pcm has been disconnected in the past 50 key cycles or something. It happens when the battery gets drained and it gets jumped. If everything seems to idle and run fine try making sure your battery is good and then disconnect the bat for 30 mins to reset the computer. See if that works.