91 jeep no spark

Partstore knows. If not sensor..then distributrcap..ign module or coil. Timing cud b off from worn chain

get new coil,and condenser

No spark can be caused by a bad crank position sensor, or a bad pick-up coil inside the distributor, especially if you can't find a signal to the coil with key on. You could also test the coil, or try a known good one. There is a test procedure for the crank position sensor, but you'd have to locate a repair manual for it. I think it's just running a resistance test across two terminals of the sensor harness connector with an ohmmeter. My son's Jeep had a bad pick-up coil that shut it down, and no spark.
Once you get it running, and if still hard starting, check the fuel pressure.

I'm a little lost here.
The 6 cyl engine uses a distributor, the V8 does not.
I don't show a part for a pick-up coil for either one.
Which engine do you have, is it a 99 jeep, and what exactly did you put in the dist hole ??

Have you replaced the crank sensor? There isn't really any way to test it, however it isn't expensive and it is fairly easy to replace. Good luck.

TO REPLACE SPARK PLUGS YOU REMOVE COIL PACK MOUNTING BOLTS THEN REMOVE THE COIL PACK WITH BOOT OVER THE SPARK PLUG.YOU HAVE 6 INDIVIDUAL COIL PACK TO EACH CYLINDER. YOU NEED A 3/8 RATCHET WRENCH - LONG 3/8 EXTENSION -SPARK PLUG SOCKET - SPARK PLUG GAUGE.AND TORQUE WRENCH.THE 2000 MODEL JEEPS FUEL FILTER INSIDE THE TANK.1993 - 1996 MODEL JEEPS FUEL FILTER LOCATED LEFT SIDE OF THE VECHICLE NEAR THE FUEL TANK.

O2 sensor will not do that. Check the basics...do you have fuel...Do you have spark? I would make a bet on it either being a crank position sensor or fuel filter. Next good guess is the ignition coil. Check these items (in order) and see what you find. Test specs are found in any manual. (if you need specifics I can give them to you. You will need a decent volt/ohm meter to test.

Well it could be many things, But have you relpaced the dist. cap and rotor, within the last 15,000 miles or wires and plugs??? next step is the coil ? then it gets fun. like timing. but I think most jeeps with a Inline 6 have a bullet proof engine for the most part. As we all know there is plenty of semi's on the road. well the same set up is there. as an Inline Jeep. I would have to say 90% of semi's on the road are inline 6 cyl. engines. and may of them go to 1million miles.
so plugs,wires, cap, rotor and ignition coil. that is a good starting point.

you need to change the coil on# 3

Check the fire at the spark plug end of the coil wires. Sounds to me like you have bad coils or coil wires.