Js2000xj

I have a 2000 4.0 xj i can’t figure the problem out. It starts up and drives fine but when I shut it off and try to start it again it either won’t start and backfire or it will start and choke it’s self on fuel. It will start backfiring and just chugging and barley holds a idle as soon as I rev it or but any load on it it will shut off. Then the intake/throttle body reeks of fuel . I can’t seem to figure the problem out. Thanks I’m advance for any help

Jim Malcolm

Heat soak. The later models have the fuel pressure regulator in the tank. Once the fuel is in the fuel rail, it has nowhere to go. Upon shutting off a warmed up engine, the heat from the exhaust manifold and cats, if so equipped, heat up the fuel, increasing the pressure. As the injectors get older, they will eventually start to leak at the higher pressure. Also, people sometimes remove the insulation thinking it's not doing anything. Adding aluminum foil around the injectors can help with the issue, but if it has just started out of no-where and the OEM insulation is still all there, it's likely an injector that is leaking...

Js2000xj

. The factory insulation is in there. Idk if it’s any correlation but my exhaust fell off right before this all started happening I don’t know if it’s a back pressure issue but my jeep ran for 6 months with the exhaust off and had 0 problems

Saudade

Is your CEL lit? Check for codes.

Js2000xj

ever since the new motors been in I haven’t been able to read codes

Saudade

New motor? Are there any other details you might want to share?