Hey all, I just bought a 1998 Cherokee 4.0 4wd with 174k miles on it. It is in pretty decent shape with no major leaks. It is pretty hard to start though, even when hot or cold. I tested the pressure at the rail and it reads around 20psi with key on engine off and around 50psi engine on at idle. This seems pretty normal, however as soon as I shut off the engine the pressure drops, and quickly. It is down to 30psi or less within 30 seconds. After 5-10 minutes there is only 2-3psi. The best I can tell it seems to be either the fuel pump (valve inside the unit) or leaky injectors. I saw people mentioning "pinching off" the fuel line to isolate and test if its the injectors or pump area, but the XJ has metal fuel lines from the tank to the fuel rail. Also a note.. the previous owner had replaced a small section (6 inches) of fuel line right below the driver door area with some rubber line where I assume the metal line had leaked or broke. Is this of concern, or nothing to be worried about?

If I try the "poor mans start" where you cycle the key several times to prime the fuel pump it seems to make little to no difference (i can get up to around 40psi while doing this and trying to start). It still cranks over for a good 10 seconds before finally firing up. It has a slight stumble at first occasionally, but hard to say for sure. Runs and idles great once its started. It has relatively new copper spark plugs and wires in it if that's of any relevance. The previous owner claimed most jeeps are hard to start like this and has done it for a while (and he claims to have replaced the crank sensor to try and solve it).

If anyone could chime in with any more testing I can do, I would really appreciate it.