Ford 5.4 Stall when Hot & Towing

Bikersmurf

Expedition Leader
Update... Thanks again.

It almost died when towing again. It started running rough when hot and he slowed down and it almost died. He was towing again.

The valves are noisy, they sound like they need adjustment (valve tick). There is also a different louder tap/is oscillation that shows up intermittently. He has been sifting through forums seeing a slew of opinions. Best guess would be related to variable valve timing.

All these sensors are miles ahead of my knowledge base... It doesn't sound like anything is majorly wrong.

He tried some 'Sea Foam' no change yet. Afterwards, 'water' was dripping from various points along exhaust.

BTW, it's got an aftermarket exhaust. The Magna-flow exhaust isn't loud at idle... Haven't heard it on the highway
 

Bbasso

Expedition Leader
Update... Thanks again.

It almost died when towing again. It started running rough when hot and he slowed down and it almost died. He was towing again.

The valves are noisy, they sound like they need adjustment (valve tick). There is also a different louder tap/is oscillation that shows up intermittently. He has been sifting through forums seeing a slew of opinions. Best guess would be related to variable valve timing.

All these sensors are miles ahead of my knowledge base... It doesn't sound like anything is majorly wrong.
Could be the cam chain tentioner, I once had to replace it on a V10...
 

camper357

Observer
Coil over plug is where I would start. My experiences was that around 100k they will start to go. Hopefully his mechanic changed those while he was doing the plugs.
 

Bikersmurf

Expedition Leader
Is it running one coil per plug? I'm not sure which you mean.

It's got 170k km so that'd be somewhat over 100k miles.
 

Bbasso

Expedition Leader
Each spark plug has its own coil on the Ford modular motors.
8 cylinders = eight plugs and eight ignition coils...
10 cylinders = etc... etc...
 

Petrolburner

Explorer
Fuel filter is cheap and easy. I swapped one coil and all the plugs on my 5.4 before changing the fuel filter. The filter was my problem. $13 and a half hour compared to the torture of changing all the plugs, doh!
 

Bikersmurf

Expedition Leader
Fuel filter is cheap and easy. I swapped one coil and all the plugs on my 5.4 before changing the fuel filter. The filter was my problem. $13 and a half hour compared to the torture of changing all the plugs, doh!

What were the symptoms?

It could be he's got more than one thing going on. The filter woudn't likely explain the excess valve noise, but it could explain the stalling.
 

Bikersmurf

Expedition Leader
He's replaced a pair of sensors that are related to the variable valve timing... It's helped a lot, I'll ask him how it's doing now.
 

gtbensley

Explorer
These trucks have a fuel pump driver module up on the frame by the spare tire. They are an aluminum housing or something like that that will crack and let moisture in. I would have him crawl under and look at that. Often as they start to go they cause a stalling or drivability issue. Its pretty simple to see. If it has damage just replace it because its bound to leave him stranded soon either way. If it looks good, just leave it.
 

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