I have a 97 E150 with the 5.4 engine. Just started stalling. It will start right up but black smoke puffs out exhaust. It will run and then stall again. Scanned but no codes present.
So checked data after problem and here's the info. Below. Checked on line for answers but confusing. Lost without a code being set.
No smell of fuel in oil, vac hoses all look good. Started right up and idles good. Drive it for 5 minutes and started to stall. O2 sensor wiring is good. Haven't checked fuel pressure or injectors.

Spark adv 23
MAF 0.947
tps 23.1
o2s B1S1 (v) 0.760
o2s B1S2 (v) 0.005
o2s B2 S1(v) 0.645
STFT b1s1 (%) 21.8
STFT b1s2 (%) na. Is this normal?
STFT b2s1 (%) 21.8
LTFT b1 % -0.7
LTFT b2 % -1.5

 

If the STFT's shown here are steady readings you have a huge problem with an overly rich running condition. Checking the fuel pressure regulator would be a good place to start. I'd also double check the intake ducting to make sure there's no huge unmetered air being drawn into the combustion chambers.

I would pull one of the spark plugs to check its condition--in your case of those readings are accurate or trusted it wouldn't matter which one to pull.

 

Thanks for the reply. I will checks these when I am back home.

 

I finally got a code that is for the purge valve stuck open. Did some research and testing, it is not coming on. There is power to the valve but it is dead. Ordered a new one along with new evap hoses. The old ones crumbling when touched. I need to take the cover off the throttle body but can't find any info on it. Some pictures of it but nothing about its purpose. Doesn't look like it is needed. Most pictures of 5.4' s do not show it on the engine. I might break it off to avoid having to remove a bunch of cables. The reason for removal is to find where the purge valve vacuum hose attaches to the TB. I need to replace it.
The hose with the valve that is attached to the trans dip stick is also bad. I couldn't get it off the mounting clip so I cut the hose and will plug the place it went into. It has never been used and seems to be in the way. Has anyone used it to diagnosis a vacuum leak or something. I don't see why it needed to be so long a hose. I think a lot of the Schrader valves are now on the purge valve. Lot of other places to check for vacuum leaks or pressure in the vapor lines.
So is it ok to remove this hard plastic cover on the TB? What about the vapor hose with the valve. Has green cap.

 

I don't recall the cover you're describing----I've had three different throttle bodies off a 2000 E-250, a 2003 E-250 and a 2005 E-350, each with the 5.4 engine. Not sure what it's function might be but as the induction system is sealed (theoretically)from the air cleaner to the inlet a cover wouldn't seem to be really necessary.

After you've replaced the hoses etc run the van without re-installing the cover---should be fine BUT after a few miles re-scan your PCM checking for any pending or confirmed DTC's.

 

It is just a trim piece to maybe help keep dirt off the moving throttle cable and such? Not sure if it has much use besides that.

 

So the purge valve didn't stop the stalling. Back to square one.

 

So I finally got a fuel pressure gauge and checked it. Pressure is 32 running and steady but when it stall it goes to 42. I don't know if it means anything. Starts up fine and pressure drops back to 32. Runs for a minute the pressure increases and stalls.

 

Checked fuel pressure again. Up to 34 and holds steady. Check fuel pressure regulator and removed vacuum hose. Pressure climbs to 44. Good vacuum on hose and no fuel in line.
Bought ForScan recommend scanner and checked about 80 % of sensors etc. All appear functioning. No codes except p1000. The p0443 is gone.
Was stalling today but when I used ForScan for an hour no stall. Rpm did fluctuate a little and and ran rough but no stall.
Need to do spark plugs and I will ck charcoal canister. I had a small amount of fuel in vapor line when I replace purge valve.
Any thoughts on what else I could check?
Might get a smoke machine and check for vacuum leaks. Already replace a couple of larger lines. Checked all the smaller ones and visually they look ok. Checked electrical connections and seem good. Wires too.
'm

 

Does it stall under load? Even just idling? A shot in the dark might be a restricted cat.

Sixto
07 E350 5.4 176K miles

 

Drove van a couple of miles and only stalled at traffic light once. Started right up. When I got home I removed the charcoal canister and it was about 1/4 full of gas. Valve on canister had a plugged vent line. The hose that come from the canister to a y split need to be replace. It is about 14 inches long.
Questions: Is the hose 5/16 or larger? What is the canister sensor called? Is it the canister purge valve?
If it is I replaced the wrong valve. Vapor Management Valve which I thought was the purge valve.

 

So I installed a new charcoal canister and purge valve. This seemed to fix the stalling problem. I also changed the spark plugs, cleaned the throttle body and replaced a couple of questionable hoses. Did this because I was on a role and it needed it. Plugs were original. Now on to the exhaust. While under the van I notice most of the exhaust hangers had rusted off the pipe. Again all factory original exhaust.
I want to thank everyone who replied to my post. You all gave me the motivation to tackle the job and not give up.

 

Thanks for your update---sometimes it pays to keep on a problem even when its frustrating as hell!