- Fuel pressure: Check the fuel pressure to make sure it is within specifications. A low fuel pressure can cause the engine to run lean and hesitate under load.
- Fuel filter: A clogged fuel filter can restrict fuel flow and cause the engine to run rough.
- Ignition system: Check the spark plugs, spark plug wires, and distributor cap and rotor (if equipped) to make sure they are in good condition and properly connected. A weak or faulty ignition system can cause the engine to run rough and hesitate under load.
- Oxygen sensor: A faulty oxygen sensor can cause the engine to run rich or lean, which can lead to hesitation and rough running.
- Throttle position sensor: A faulty throttle position sensor can send incorrect signals to the engine computer, which can cause the engine to run rough and hesitate.
- EGR valve: A stuck or faulty EGR valve can cause the engine to run rough and hesitate.
- Vacuum leaks: Vacuum leaks can cause the engine to run lean and hesitate.
- Computer problems: A faulty engine control module (ECM) can cause the engine to run rough and hesitate.
If you are unable to diagnose and fix the problem yourself, it is best to take your Wrangler to a qualified mechanic for further diagnosis and repair.
