I need some help…My 2000 Jeep TJ 4.0L is losing power at random times while driving. It starts to sputter and is not responsive to pressing the accelerator. Just when I think it will come to a complete stop with no power it seems to rescue itself and then operate normally although it seems like it idles higher after recovery.. It is currently throwing off two error codes…PO 132 and PO 138. Those codes continue to come up even after I replaced the both 02 sensors(I have Fed emissions). I have also recently replaced with IACV and throttle position sensor. In the last four years I have replaced the fuel pump four times. Any ideas what else I should do to diagnose this problem. I live in Costa Rica and finding quality advice can be challenging.
4.0 losing power randomly
- Thread starter drcomf22
- Start date
Check the fuel pressure and better yet put a gauge someplace you can monitor it while you drive.
If you have a way to read live ODB data monitor O2 sensor voltages and fuel trims. A cheap $20-$30 Bluetooth reader and the free Torque Lite app can accomplish that.
You fuel pressure should be 48-50 psi.
O2 voltages should generally range below .9v. Fuel trims should be low single digit numbers.
Bueno suerte!
-Mac
If you have a way to read live ODB data monitor O2 sensor voltages and fuel trims. A cheap $20-$30 Bluetooth reader and the free Torque Lite app can accomplish that.
You fuel pressure should be 48-50 psi.
O2 voltages should generally range below .9v. Fuel trims should be low single digit numbers.
Bueno suerte!
-Mac
Given the symptoms you described and the error codes you’re seeing (P0132 and P0138 relate to the O2 sensor circuit, specifically the bank 1 sensor), here are some things to investigate:
Electrical Connections: Since you've already replaced the O2 sensors and other components, check that all electrical connections and grounds leading to those components are clean and secure. Corrosion or a loose connection can cause intermittent issues. I'd also thoroughly (this will take you a long time to do right) check to make sure you don't have any breaks in the wiring. I can't stress this enough!
Fuel System: Given that you've replaced the fuel pump multiple times, it's worth checking the fuel filter and fuel lines for any blockages. Not something that's very common, but it's worth ruling out. Also, consider testing the fuel pressure to ensure that it's within spec.
Vacuum Leaks: Inspect for any vacuum leaks that could affect engine performance. Even a small vacuum leak can disrupt the air-fuel mixture. Use brake cleaner or carb cleaner to spray around vacuum hoses and listen for any changes in engine idle.
PCV Valve: A malfunctioning PCV valve can also cause rough idling and performance issues.
Idle Air Control Valve (IAC): Since you mentioned you've replaced this component, make sure it was correctly installed and is functioning properly. A malfunctioning IAC can cause high idle and issues with responsiveness.
Engine Timing: Ensure that your engine timing is set correctly. If the timing is off, it can lead to performance issues.
PCM: Consider taking your Jeep to a mechanic who specializes in electrical diagnosis. A professional scan tool can read live data from the PCM and will tell you quite a bit in regards to what is going on when it loses power.
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