spjohnson1031

Hey all,

I have a 2001 Cherokee Sport (4x4, 4 door, 4.0L). About 3 weeks ago, my Jeep stalled inexplicably while I was rolling at about 3 mph (foot not on accelerator). I didn't think much of it until later that day when it threw a check engine light. Turned out to be a cylinder 3 misfire. The light went off and the Jeep was driving fine.

Two weeks later it stalled again, 3 times in one night. Two of the times it stalled while sitting at a light and once while I was rolling at about 5mph (same as described above).

It would also lose power for a brief second while going along at about 40mph (felt like I lifted off the accelerator but I didn't). No stall, but it stumbled and then recomposed itself. It's done this several times now.

Every time it's stalled, it's started right back up afterwards, no issue or hard starting. Since I bought the Jeep a year ago, I've always had to prime the fuel lines with the key in the "run" position because the lines don't hold pressure. After priming the lines, it always starts right up with no hesitation. It will hold enough pressure to start again without priming for about an hour. The person I bought the Jeep from told me it had a new fuel pump.

I sent it to my mechanic who drove it for a week and experienced the symptoms (only 2 stalls and one loss of power) throughout the course of the week. He could not diagnose the issue and gave it back to me as is. He said the first time it stalled it cut power to his scan tool and the second time it didn't.

I have cleaned the throttle body and IAC and that's about it. I've noticed a lot of people have replaced either the CPS or MAP sensor to solve this issue but I'm not willing to replace parts without a diagnosis. The Jeep's idled rough since I've had it but that may just be a Jeep thing. I went to autozone today to rent a fuel pressure tester and it told me I was getting less than 10 PSI with the vehicle running but I'm 90% sure the gauge was broken because I still daily drive the car and 10 PSI doesn't seem like enough to move it. I do have a crack on my rear CCV hose (replacing tomorrow). Would this cause these symptoms?

I'm beyond frustrated and looking for ideas or anyone who's solved the same issues? Any help is appreciated! Thanks in advance.

jordan96xj

1. Fix the CCV hose to remove that variable
2. Get a working fuel pressure gauge and get some actual readings, especially good if you can have it on and reading when one of the symptoms is happening.


The symptoms do sound suspiciously like a fuel pump, but a failing fuel pump won't typically take out the OBD diagnostic port. Unless there is a larger electrical problem going on that is effecting both the fuel pump and the diagnostic port. However, a failing CPS sometimes will effect the diagnostic port. Many people complain of not being able to get OBD2 readings until replacing the failed CPS sensor.

I personally helped a neighbor with a 01 that had a failed CPS. The vehicle was fixed definitively by replacing the CPS. While the failed CPS was in place, we were not able to scan the OBD2 data. This in itself can lead to some extra clues that help, for example, dash cluster gauges that depend on the computer/obd2 data for displaying will sometimes fail. In my neighbor's case, the fuel gauge and voltmeter would fail to display a valid reading when the failed CPS was connected. When we disconnected from the failed CPS, they would display normally.

If you can get OBD2 readings with CPS disconnected, but NOT with it connected. I would definitely suspect the CPS. But if the CPS is only intermittently failing right now, that can be tough. In my neighbor's case, it was fully failed.