Hello everyone,

I need a bit of help from the group here. I have a 1994 E150 5.8 E4OD Explorer Conversion Van Hi Top than is in excellent shape. Bought this can from Copart back in Aug. 2023. Once in my possession, I pulled the 5.8 and completely freshened it in December 2023. Replaced many parts on van not because they were out but just so I would know the history, since it will be driven a lot on long distances. Replaced, fuel pressure regulator, fuel pump assembly, had all 8 injectors flowed and checked, TPS, coil, MAP, EGR valve and ECM (died with no start condition early 2024). Got lucky and found exact matching ECM from Ebay, refurbished. Installed new ECM and all good. Again, in early 2024 I got a 1993 E4OD from junkyard f250 and sent to John Wood in CA for total rebuild. There was nothing wrong with my original 1994 E4OD that was in van when I got it; just wanted a fresh one, that I know history of. Got new tranny back from John Wood and installed in 5/24. Fresh up to date E4OD with new converter and latest 1996 valve body. Re-pinned new 1996 and up connector on my 1994 for the updated E4OD I installed.

In May 2024, I started driving the van a lot, with no issues. Took many 250–400-mile trips. From the time I put new tranny in 5/24, up until 5/25 I have put approximately 7500-8000 miles on van with it running just fine. About a month ago, coming back from 300-mile trip, I noticed a surge/hesitation driving at speed on the highway, in overdrive. I have checked fuel pressure which is fine. I haven't been able yet to find why I have this surge/hesitation in overdrive, at speed. Haven't found any obvious vacuum leaks. I feel like something went out, since all was fine the prior trip and many miles (7000-8000) prior. Could the expertise here please chime in, and offer any assistance/advice on where I should focus my troubleshooting? I would appreciate hearing any similar issues and resolutions. I've been driving it with the doghouse removed, so I can actually see the engine under load and monitor fuel pressure, vacuum and such. It was running so perfect, then bam, this all started. Please help! Ask all the questions you want. I'm an open book.

 

I'll update since I've been doing tons of research. What I didn't mention in my initial post was some previous erratic shifting but nothing too severe, until day before yesterday. Decided to swap my other good PCM in and just try it. Well, as I expected, it made no difference. Still had the surge at speed, along with some erratic low speed shifting from the E4od. My OD light is not on, the cruise control works fine, and my speedometer is steady and not bouncing. Seems this is probably my PSOM heading South, fast. Pulling dash cluster out tomorrow and sending to Cluster fix for a check and repair if needed. Will return back and update with results.

 

The fuel system is likely causing the surge
My 94 1/2 ton with a 5,8 surges too
Basically, if you are tuned into the surge, you can feel it at any speed at part throttle drive away
I can feel mine surge at any speed if I drive part throttle and "feel" for it
Used to put timing gears in old Lincolns that surged and that fixed some of them
By the mid 90's and adaptive fuel control, the timing chain wear didn't matter as much and the surge was barely noticeable
You can spend a ton of money trying to fix a NORMAL surge on a 5.8l Ford of your era
Get several opinions before spending a ton of money on it
I'd have a few Ford dealer drivability boys drive and evaluate it

 

Are there any codes stored in the PCM?

 

I drove the van for about 15 minutes on 7/31, came back parked it and immediately ran KOEO. Got code 452 only. I assumed it was PSOM related, as I have been reading the forums for months now and having erratic shifting issues, along with the misfire/surge in OD under light load. Pulled my original dash out and can see some damage and black goo on my PSOM module. Now, luckily, I found in the salvage yard (earlier this year) another 1994 E150 and grabbed the dash cluster. I swapped it out about two days ago, 8/1, and drove van. The shifting was perfect, smooth, no holding gears but still had misfire/surge in OD under light load, starting about 45 mph (doghouse is off, so I can visibly see engine shaking one reaching that speed). I parked van, and disconnected battery.

I did not have a chance to pull codes until today 8/3. Drove van for about 15 mins today (still have misfire/surge in OD under light load), parked it and immediately ran KOEO. Only code was 111, so I moved on to run KOER and only got 111. So, engine was up to temp, ran KOEO and KOER and have no codes that point to anything. One thing I did make note of was when I turn the key on and fuel pump runs; pressure runs up like normal, but the pressure doesn't hold. It comes back down immediately. When driving though, the fuel pressure is fine and has the appropriate pressures everywhere (fuel pump assembly is new). Also, today, 8/3 I checked and rerouted the plug wires according to the Ford TSB but I didn't think my issue was there and it wasn't. Any ideas where I should go next? As much as I love my Fords, I'm frustrated.

 

I've seen several references to the fuel pressure being "fine" and you watching fuel pressure as you drive.

What are the actual pressure readings?

Have you tried same conditions with overdrive locked out?

Have you tried same RPMs as when it happens in Overdrive, but while in 3rd with overdrive locked out?

Have you tried keeping the torque converter clutch from engaging?

 

Thanks for the response. I will drive the van an get actual numbers for fuel pressure. Fuel pressure was one of the first things I checked months ago. As I recall, it was normal at ide ~30psi, close to ~40 with vacuum removed form regulator and would rise quickly when driving under load but I can get real numbers. Also, as I recall, turning off OD and staying in 3rd up same approx. rpm (van has no tach) I didn't feel the surging, but I will go back and do the checks over again. I not familiar with how to keep TC clutch from engaging. Is there another check I can do which I'm unaware of?

 

Okay, drove van today and got some good information that I hope will jog the brains here and give me some good pointers for diagnosing this issue (OD = overdrive). I'm desperate to get this resolved. I took fuel pressure numbers at all the conditions below and recorded the other conditions below while driving with doghouse off.

Fuel pressure at idle: 30psi
At idle and tap the throttle: quick jump to 37 psi
Cruising in 1st gear: 32psi
Cruising in 2nd gear: 35psi
Cruising in 3rd gear with OD off: 35 psi
Cruising at 65 mpg in OD: 30-32psi
Floor the throttle at 55 mph: 38 psi
In OD at 50 mph and easing into throttle: 35-37 psi
Vacuum at idle in drive: 19
Vacuum at idle in park: 21


No matter what I do I'm still getting this surge/stumble/misfire, engine shake but smooth as butter going through 1st and 2nd gear

Cruising in 3rd gear no/OD 35 mph (bad misfire/shake this where start feeling misfire and visibly see engine bucking) Stumble is there whether in OD or not.
Cruising in OD 45 mph (bad misfire/shake very noticeable)
Cruising in OD 50 mph (bad misfire/shake THIS THE WORST and most noticeable mph) Engine seems it's trying to jump out of the mounts.
Cruising in OD with cruise control on at 65 mph (bad misfire/shake is there and can feel in the movement of the vehicle back and forth, it's so annoying at this speed)

 

Fuel pressures seem a bit low. This is with a fuel pressure test gauge connected to a test port, right?

What make and model are the new fuel pump and fuel pressure regulator?

How many miles are on the spark plugs?

How many miles are on the spark plug wires?

How many miles are on the distributor cap?

How many miles are on the rotor?

 

Just a quick note, so I can explain what I did with this van. Bought van (1994 E150) August 2023 from Copart. Van was running fine when delivered and had 193k on odometer. Drove van a couple months as delivered from Coparts. In Fall of 2023 I preceded to update everything. Removed 5.8 and freshened (professional job done by excellent machine shop, cost 2k), new spark plugs with new engine, new fuel pump assembly, new EGR valve from Rockauto, new cap, new rotor, new Motorcraft ignition module, new Motorcraft coil, new Motorcraft TPS, new Motorcraft MAP. Distributor is not new and is still the original 1994 it left the factory with. Van had sticker on windshield saying it was last serviced by Damerow Ford in Oregon (I'm in Texas). I called them and they confirmed by vin what was done, coolant, fuel filter changed less then 2k ago according to odometer. I pulled filter off to check and blow through. It was new. Also, I did not change plug wires (until March 2025)

I grabbed 1993 E4OD from junkyard, sent off to John Wood in CA and had it built (didn't install until May 2024). After adding all the new stuff, started driving van a lot starting in early 2024. The only issue I had was the ECM died in Feb 2024. Found exact refurbished match on Ebay and bought it. Sent my original ECM off and had it repaired and tested. I have two good proven ECMs now. In May 2024, new E4OD with new TQ converter was installed. John Wood uses the 1996 up valve bodies in his E4ODs so I had to re-pin from my 1994 connector to 1996 up connector (no issue there). Drove van a lot from May 2024 (probably 7k miles with new trans) until April 2025, where this current issue popped up and here, I am. On about a 250-mile round trip and started noticing the surge/hesitation (April 2025) in OD on highway. Still trying to figure this out.

Fuel pressures seem a bit low. This is with a fuel pressure test gauge connected to a test port, right? Yes, pressure gauge connected directly to driver side rail.

What make and model are the new fuel pump and fuel pressure regulator? New pump assembly Fall 2023 (O'Reilly precision brand pump and Standard fuel pressure regulator

How many miles are on the spark plugs? Spark plugs have about 9k miles on them

How many miles are on the spark plug wires? Bought new set of Motorcraft wires in March 2025 and changed them. Only changed wires so I would know they were new. Wires that came with van weren't original and weren't old, but I changed anyway.

How many miles are on the distributor cap? New cap Fall 2023 about 9k miles on cap

How many miles are on the rotor? New rotor Fall 2023 about 9k miles on rotor

It's driving me nuts that I'm not using my van. Any and all help is greatly appreciated!

 

Just a quick note, van already had the new Motorcraft spark plug wires on it when it started doing the surge/hesitation.
New wires added March 2025
Noticed surge/hesitation April 2025.

 

I would be looking inside the processor again
I would disconnect the spout and see if it runs any better without the processor controlling the timing
You said OEM distributor
** Put a stator in it (DU-50C Motorcraft) almost impossible to find a Ford one these days

 

Thanks for the response, @manicmechanic007. I going to also put this out there for reference information. My daily driver for the LAST 29 years has been my 1992 F150 step side with 5.8/E4OD. Got truck and 24 yrs old in 1996 and still driving this same truck right now at 54 yrs old (about to go move a piece of furniture for friend after I type this). I'm totally in tune with 5.8/E4OD combo and know how it should feel when driving. This annoying surge/misfire with the E150 is killing me.

I'll pull spout, drive van and see if anything is different. Also, I have several junkyard acquired hydraulic roller 5.8 distributors and could swap my original out, to see if that cures the issue. I also have the repaired original ECM and could swap that and try also. Any help/ideas at this point are greatly appreciated!

 

I feel like we're missing something like a broken vacuum line or thereabouts.

 

Since I was driving when I noticed the surge/misfire begin, do you think maybe a vacuum line broke and started sucking unmetered air?