I just bought an 83 XJS with 59k miles on it. It starts when it is sitting in the sun, but not when it is a cool day or sitting in the shade. It just continues to crank and has spark at the coil. The gentleman I bought it from said fuel was coming from the fuel rail, however after reading many posts...I see that it could pump fuel but still be too weak to start the car. My guess and it is only a guess, is that the sun is heating the car and building pressure in the tank and creating more pressure and allowing the car to start. I am guessing that once the car is started that the pressure will equal out and the car will then die if I was to drive it. So this is why I am thinking fuel pump...I know its a goofy theory right? If you view it please just let me know if I am in the right direction.

Thanks for any posts that could help.

-s