help!!!

ok today i get in my xj and a crank it up and it back fires loud almost like and shotgun and then when its running its skippin bad... so i cut it off check the plugs, wires, rotor cap, ect. then i thought it might be the timing belt and a tooth broken off then i find out its got a timing chain so it cant be that and im lost!!! help

Description of your xj? Timing chains can stretch, partially disintegrate as mine did and I guess eventually break.

its a 89 cherokee with the 4.0 4wd manual anything else you need to know?

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