So when my XJ sits for a while it cranks but won't start, just had my ole lady rock up and down in her door jam and it cranked right up? What's the deal? Fuel pump? Idk what else it could be

 

What year XJ are we talking about? Could also be a pressure regulator, leaky injector, etc. don't throw a fuel pump at it just yet. Usually when you rock it and it starts that's a sign of old gas. How long did it sit?

 

Over night, just filled it up a few days ago. And it's an 89.

 

Check the fuel pressure to see if it's bleeding back.

 

Probably coincidence with the rocking and rolling.

click on my link below and do tips 1,3,4, and 5.