* Alternator: This is the most common cause. The alternator is responsible for charging the battery while the engine is running. If it's failing, it might initially charge the battery enough to start, but then fails to keep it topped up, leading to the rough idle and stalling. Test the alternator's output voltage while the engine is running. It should be around 13.5-14.5 volts.
* Battery: Even though you've charged it, the battery itself might be failing internally. A failing cell might accept a charge but not hold it effectively, or it could have a short circuit that drains the battery while the engine is off. Get it load-tested at an auto parts store to be sure.
* Starter Motor: While less likely to directly cause the rough idle and shut-off, a failing starter motor can draw excessive current, rapidly depleting the battery. If the starter is sticking, it might create a significant drain.
* Wiring Problems: Corroded or loose connections in the charging system (battery terminals, alternator connections, etc.) can prevent proper current flow and cause similar symptoms. Check all connections for corrosion and tightness. Look for damaged or frayed wires, especially around the battery and alternator.
* Ignition System: Problems with the ignition coil, distributor cap, rotor, or spark plugs/wires can lead to a rough idle and stalling. A weak spark can cause the engine to misfire and eventually die.
* Fuel System: A clogged fuel filter, failing fuel pump, or issues with the carburetor (if equipped) can starve the engine of fuel, leading to stalling.
* Sensors: Various engine sensors (like the crankshaft position sensor or oxygen sensor) provide crucial information to the engine's computer. A faulty sensor can cause erratic operation and stalling.
Troubleshooting Steps:
1. Test the alternator: This is the most crucial first step. Have the alternator load-tested at an auto parts store.
2. Inspect all wiring: Check for corrosion, loose connections, and damaged wires in the charging system. Clean or repair any issues found.
3. Check battery terminals: Ensure they are clean, tight, and properly connected.
4. Test the battery: Get it load-tested to rule out internal problems.
5. Have the ignition system checked: Inspect the distributor cap, rotor, spark plugs, and wires. A mechanic might need to test the coil.
6. Check the fuel system: Examine the fuel filter for clogs. A mechanic can test fuel pressure.
Important Note: An 89 Jeep Cherokee is an older vehicle, and some of these issues might require specialized tools and knowledge. If you're not comfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Ignoring the problem could lead to further damage.
