Maybe thats the ticket. He said it only does it coming to a stop. Maybe at high speed, the HPFPs are operating enough to pull fuel up, but when he drops down to an idle, the fuel stops flowing? Just brainstorming at this point. Mystery problems are so difficult when you can touch and see whats going on for yourself. I'd love to know what pump voltage is doing during this stall. Also, he stated there was no engine light, but I never saw where he said he checked for codes. Maybe it has a P0087 or something and the light never came on?

Could be. As you said, its tough when its not here.

The sport I rigged up the kill switch on would run and finally throw a code, but never died. I didn't try to drive it either though.

I have the same problem with my LR4 dies all the same parts have already been replaced all the fuel pumps etc.. please help

the problem is a fuel pressure sensor located next to the transmission bell housing, on the passenger side , you need to access it from the bottom of the car , once it warm up it’s shorted inside , part cost is 60-80$

Thanks I will have them try that.

Here’s a video right after my car died while I was parking at the post office. Put it into park and boom, it died. I restarted the car and just sat for a few minutes. Then I began hearing what I guess is pinging and the rpms started doing what you see in the video. I gave it some steady gas to try and help even it out.

This is the second time it has happened in the last day. I have a GAP tool, does anyone know what I lookup in the live values to begin diagnosing the problem? Anyone have this happen to them? It’s a 2011 v8 with 133k miles on the clock. Thank you.

No video appears to be attached/linked to your post. What diagnostic codes are showing?

The video isn’t uploading, but the rpms drop in a rhythmic way. Each drop gets worse until the battery light comes at the bottom of the drop but the engine “saves it self” and the rpms go up. Never over 1000, though. It’s not throwing any codes or anything.

Does the engine do this when it’s cold or only hot?

I guess I’d start with your battery and alternator - just make sure its healthy. Tough to diagnose much if your battery is not up to snuff. Engine running, you should be seeing 14v+. Engine off - battery really should be at 12.6v, but there will be a current drain for up to about 15 minutes after shut down. So when you first shut down, you might see 12.2-12.4v. If you wait 15 min, you should be seeing about 12.6v or so on a multimeter.

Then I’d probably start by looking at fuel trims, o2 readings, and fuel pressure. Fuel trims should be within +/-10%. When its surging, the short term might be bouncing around a lot, but look at both. Your overall is the total short+long. High positive fuel trims indicates a lean condition, like a vacuum leak (possibly a torn pcv). High negative fuel trim indicates a rich condition.

When the car is warm and running in closed loop fuel control, your first position o2 sensors should be going back and forth from about 0.2v-0.7v or so in a smooth wave, up and down.

For fuel pressure, the GAP tool should show commanded and actual fuel rail pressure. These should be close to the same value.

thank you! I’ll start going through all of this tomorrow and report back.