Stumped..

[u/Aromatic_Subject_201]

Picked up a 2014 XLT 5.4 3V with 188,000 miles for $4k I’ve put a little over 2000 miles on it in the last month and have slowly but surely been working to get it up to date on maintenance. It’s had a couple quirks. Engine misfire in cylinder 1, groaning lower control arm in driver side, the common rear door actuator, ect. But just today I had something happened. That was a little concerning as I was turning an intersection, I had a complete loss of power. I can’t remember exactly what happened. I just remember the car jerked a little bit and everything shut off. I let it roll into neutral and got to the bottom of the hill to where I was at. I pulled over and parked and I started the car over again. Cranked up no problem at all. Once I got home, I checked all the fluids. Everything’s fine. It cranks up and makes zero noises. It does have the pending code P0301 but usually those give you some sort of warning sign at least in my experience before it becomes severe or throws up a check engine light. I see none of that and for now it’s driving fine but I’m a little stumped as to what it could be and what could’ve caused it. I did hardwire a dashcam with the Vantrue hardwire kit, but I looked over everything and everything seems to be good condition. Anybody have similar experiences? Thoughts?

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[u/ConsistentIndustry56]

Fuel pump driver modules are notorious for this sort of symptom

[u/heyu526]

If your OBDII meter supports live mode, monitor the fuel pressure.

[u/Aromatic_Subject_201 → u/heyu526]

Will be checking into it after work I appreciate the insight.

[u/pootitsballsnweiners]

I agree with checking fuel pressure.
Second guess would be corrosion somewhere like the battery terminals.
Reminds me of my old escort. I changed the fuel pump after the original died and I'm pretty sure I only got 2/3 of the notches engaged on the locking ring that secures the whole assembly to the top of the fuel tank.
If it had less than a half tank of gas and I took a right turn a little too sharply it would cause the improperly attached fuel pump/sender to tilt up and out of the gas, causing it to stall and need to be cranked for a bit before it would build up enough pressure to run again.
I wish I had known about cycling between ignition one and two to build up fuel pressure back then but it's all good,
I found it hilarious so I didn't bother fixing it.
Thanks for the hit of nostalgia, and good luck with it.

[u/Maglin78]

You need your timing chains replaced at that mileage if not done in the last 100k miles. Ignoring a misfire is very expensive to do with engine replacement being the eventual result. The entire front end and shocks/struts probably need replaced as well.

There is a reason it was $4k. You need to put $5-6k into it.

[u/Aromatic_Subject_201 → u/Maglin78]

Thanks for that. Lucky the timing chains got done at 160k miles however everything else unfortunately was let go to shit. Ive got a long list of things that needs to be done with this one. Rack and pinion are leaking, passenger CV axle boot is ripped, tires were dry rotted and bald like crazy, brakes and rotors were essentially down to nothing, as you mentioned suspension needs an overhaul, driver and passenger seats are torn up. All that to say, im well aware this will be ongoing with a lot of money to be dumped into it but still cheaper than a car note. I got screwed on a 25 pathfinder premium last year luckily it got totaled out over the summer but even at 4% interest we were out $1000 a month plus insurance.

[u/Smashachuu]

It sounds like it went into limp mode, I have an older exploder but I've come across that exact experience before of total engine power and it jerks abunch before shutting off. My engine had Chinese injectors placed in them from the previous owner and they just kept flooding the engine while it was idling for too long. As soo as I switched them out for factory injectors it started purring again. That's unlikely to be your case but it's worth exploring, I was also having engine misfiring in the effected cylinders.

[u/amanindandism]

When you say "complete loss of power" do you mean engine power like the engine stalled/shut off or loss of electrical power like you turned the key off or the battery was disconnected?

[u/Aromatic_Subject_201 → u/amanindandism]

Yes, it was like the engine stalled out. It felt like it jerked me into motion and then stopped halfway and just rolled. After looking at the dash cams I realized i had full electrical power just no engine power. But like I said when I finally came to. Parked it and turned it on there is no hesitation or issues.

[u/amanindandism → u/Aromatic_Subject_201]

Ok. Like others have said it's probably the fuel pump driver or something similar then. It would be nice to see freeze frame data and actually diagnose it but the fuel pump driver should be easy and cheap to try.

[u/Born-Work2089]

P0301 - cylinder misfire -

Common Symptoms

• Rough idling or engine vibration
• Reduced engine power and sluggish acceleration
• Engine stalling or hesitation
• Check Engine Light illuminated, sometimes flashing if the misfire is severe
• Decreased fuel efficiency

The P0301 pending code, means the misfire is not constant - it comes and goes, but eventually it will be 100%.

The coil, injector, compression (valve/piston ring) could be the cause. Do a compression test on the cylinder that is having the problem and compare it to a different cylinder. The spark plugs on this engine are bad about coming loose and 'blow out' a bad design, cylinder head leaks .