I have a 99 wangler sport 4.0. After I drive it for around a hr it wants to skip and sometimes stop running. Once I cools off it runs grate. Work I have done to try in fix this is, throttle position sensor, coil pack ,spark plugs and wires and distributor cap. I was also told it could be a fuel injecter or my crank position sensor. It shows no codes when this happen. if anyone can help please do I'm lost and in normally good at pinpointing my problem. Thanks
99 wangler wants to skip
- Thread starter Taysmith
- Start date
JPNinPA
Active member
What temp are you at when this happens?
Check your fuel pressure.
Any exhaust leaks?
Any vacuum leaks?
greg92jeepxj
Official Supporter
Welcome to jeeps.com. You've replaced quite a few parts but I hoped the quality is good or you could end up,with more problems. Be careful to avoid the parts changing pitfall that we can easily fall into. No dtc's isn't always a dead end. Just means you've got to work for it. The answer is to check if the sensor(s) you suspect is in range . Since it is possibly related to temperature , you might want to check the CTS ( coolant temperature sensor) readings if they're in range. Of the temperature seems stable , check oxygen sensor readings as well. Your fuel system could be running lean causing a miss.
greg92jeepxj
Official Supporter
It's sounding like a sensor is causing a drivability problem . An oxygen sensor comes to mind but we still caution you to get good quality parts of you need to replace one. Before you just throw parts at it on a guess , a scan tool could tell if sensors are out of range . A repair manual with proper specifications will be needed . If a scan tool isn't available . A good digital volt meter that is automotive approved and computer safe can be used as per the manual.
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JPNinPA
Active member
What kind of plugs? Brand and PN?
What was the fuel pressure reading?
Fixed vac leak how long ago?
Bounty__Hunter
Super Moderator
Check for a TSB issued by Chrysler concerning heat soak of the injectors on 4.0L TJ's. The fix is a heat shield on the intake manifold.
