4.7 stalling while driving and idling FIXED!!

[Smokey Ram]

I got a 03 slt 4x4 auto 4.7 with 312k original motor and trans, maintained really well, recently it’s developed a stalling issue.

It started one day when I left a gas station after filling up, I was accelerating to pass someone, the truck downshifted fine and the torque of the 4.7 kicked in, once it got past 3k rpms the truck shut off and lost all power, I couldn’t start it in neutral I had to pull over and put the truck in park then turn the key off and go to start it. Fired right up and went on with my day, that same day it did it again while merging onto a road, same process of shutting off the pulling over to restart.

It does it on the highway while passing too, I replaced my fuse box due to my headlights and taillights not working and it seemed to have fixed the issue for a couple weeks till the truck stalled while cruising at 100kmh I wasn’t on the gas and it quit.

Now with winter here, when I cold start the truck, it won’t stay idling for more then 2 minutes without stalling the same way.

I have no CEL at all, I hook up a scanner and there’s nothing stored in the truck, I’ve seen a couple threads here with similar problems but no follow ups from OP.

Any help is much appreciated I’ll update as I figure it out

Edit December 25th 2021:
Its fixed, was bad coils, replaced them with NGK coils and replaced plugs with oem champion copper ones, truck runs great now!

 

[Recoil]

Could it be a possible fuel issue? Have you checked your fuel pressure at the rail?

 

[kevkev]

Check you ignition switch in your column. Might be burnt.

 

[Lufty]

I had a ‘04 Dakota with a 4.7 for 15 years and when it got cold my pcv valve would sometimes freeze shut from the milky build up in the oil fill tube (where the pcv valve is located and a crappy design by the way) and it wouldn’t stay running/stall unless my foot was on the gas and the heat would finally free it open. So every fall I would just replace the pcv valve so it was clean and moved freely. Something easy to try for a couple of bucks. Good luck

 

[Irishthreeper]

Had a very similar problem years ago on an old 4 banger truck. It was intermittently starving for fuel and after looking at a wiring diagram it ended up being a bad wire running off the alternator that fed the fuel pump relay. Weird but it fixed the problem.

 

[Smokey Ram]

Could it be a possible fuel issue? Have you checked your fuel pressure at the rail?

Its possible, the pump is the original one however every time I turn the key that pump still primes like new, like its pretty loud and doesn't sound weak. Do you know what the fuel pressure should be on these trucks before I test it?

Check you ignition switch in your column. Might be burnt.

The ignition switch like where the key goes? What do you mean by burnt? You mean broken? That is a possibility. It takes a little bit of jigging the key for it to go past the off position but its been like that for many years

I had a ‘04 Dakota with a 4.7 for 15 years and when it got cold my pcv valve would sometimes freeze shut from the milky build up in the oil fill tube (where the pcv valve is located and a crappy design by the way) and it wouldn’t stay running/stall unless my foot was on the gas and the heat would finally free it open. So every fall I would just replace the pcv valve so it was clean and moved freely. Something easy to try for a couple of bucks. Good luck

Just replaced my pcv for the first time in a long ass time. I'll check it again today because as you mentioned the pcv system is indeed poorly designed on these trucks

Had a very similar problem years ago on an old 4 banger truck. It was intermittently starving for fuel and after looking at a wiring diagram it ended up being a bad wire running off the alternator that fed the fuel pump relay. Weird but it fixed the problem.

That reminds me, I was thinking it could be a bad ground strap, I picked up a cheap but complete 4.7 to hopefully build in the future and its ground straps were pretty corroded. Might be worth checking that
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On a side note, there is a YouTube video on a 4.7 ram and a guy fixed his issue with new coils, I had just ordered new coils and bought some new plugs (Champion RC12MCC4 Copper plugs, same ones that the factory put in these trucks) but ill still check your guy's suggestions till the coils come in the mail

 

[Recoil]

Fuel pressure at the rail should be between 44 and 54 PSI.

 

[Smokey Ram]

Fuel pressure at the rail should be between 44 and 54 PSI.

Is that at idle or when its primed with the key

 

[Smokey Ram]

I had a ‘04 Dakota with a 4.7 for 15 years and when it got cold my pcv valve would sometimes freeze shut from the milky build up in the oil fill tube (where the pcv valve is located and a crappy design by the way) and it wouldn’t stay running/stall unless my foot was on the gas and the heat would finally free it open. So every fall I would just replace the pcv valve so it was clean and moved freely. Something easy to try for a couple of bucks. Good luck

I checked the PCV before I started the truck and its mint, was still pretty clean.

I replaced it a little over a year ago thinking I had a oil consumption problem but it turns out I was leaking it rapidly so I just went to a thicker oil.

 

[Recoil]

Is that at idle or when its primed with the key

Take a reading when it is primed... Then take another reading while the truck is at idle.

 

[Smokey Ram]

Good news! Seems like the coils actually fixed the stalling, strange because wouldn't a bad coil cause a miss fire or dead cylinder? I would've never thought a bad coil would cause the truck to shut off completly..

Take a reading when it is primed... Then take another reading while the truck is at idle.

I'm curious what i get, ill try this anyways to see how the old pump is doing

 

[Dodge trucker]

My 96 Dakota with 318 Magnum just did this to me yesterday. It wound up being a bad crank sensor. made me late for work, while I was waiting for a ride on the side of the road, I opened the hood and started shaking wires, when I shook the ones coming from the crank sensor I was able to start it and get in to work.It did it again 2x on the way home from work. No check engine light or code, while it was acting bad I had no communication with my scanner, also noticed the check engine light wouldnt come on when I first keyed up (usually comes on as a bulb check) and I didn't hear the telltale few second buzz from the pump. When I "woke it up" by shaking the harness from sensor I first heard the pump (I was under the hood, couldnt see the dash)
while the sensor was dead and the computer wouldnt communicate, it couldnt set a code. (or it did and erased itself) on the older trucks before P codes you could get a Code 11 sometimes when the crank sensor died. The 1st couple of years of P codes on Dodges sometimes the computer would spit out P codes, sometimes codes under the "old way". My 97 1500 did teh same years ago. I shut it off at the gas pump and it wouldnt restart. That time I did get a "code 11"
I got a ride, went and got a new sensor (was gonna replace it at the gas station) and when I got back, it fired right up. so I got it home (had my "ride" follow me to be sure I made it)
When crank sensor goes out you lose tach signal even while cranking. As I remember if it is cam sensor (distributor pickup on those trucks) died, you wouldn't.