I have a 2003 that runs rough after you shut it off and start it again after about 10 minutes or so of heat soak. I can drive 100 miles, and it is still running fine until I shut it off. Otherwise, it runs great.

I have done lots of maintenance to this truck and I am out of ideas.

I have replaced all of the following some twice or 3 times:

HPOP
LPOP and cover
Injectors (warren diesel rebuilt)
Both engine wire harness and FICM wire harness
IPR 3 times, last one was verified OEM came in a static bag with silver sticker
ICP 2 times Last one was verified OEM from Proven Diesel and says FoMoCo on the body of it.
Replaced the oil cooler and screen with Ford OEM cooler.
Checked FICM voltage via Autel scanner while the problem was happening and it said 49V

Last thing I noticed was my running voltage via the scanner was 12.9v - 13.1v Not sure if this will cause any issues.

Does anyone have any items I should check at this point? Any other troubleshooting steps I should take?

Thanks for any help with this.

 

This may be kind of a long shot, but it should be ruled out. Check the alternator for AC ripple voltage. You can do this with a multimeter set to AC or with an oscilloscope set for AC coupling. Get the ground from the alternator frame and the power from the output stud on the alternator. You should see less than about 0.05 VAC.

 

Thank you for that troubleshoot tip!

I will do that a bit later today!!

 

You should post up all your sensor values when it is currently misfiring

@idle and during misfire event
@ 2500rpm during
lastly @koeo during

 

What are the codes

 

sounds expensive

Struggling to get enough HPO??

all this recent work ??



can you post a picture of oil filter house??

 

A static bag with silver sticker can't be counterfeited? FoMoCo labels can't either? Packaging is counterfeited just like parts.

The proof of authentic parts is in the place of purchase IMO.

Codes are very important, but you must be using one of very few specific scan tools to be assured that ALL codes are being retrieved. FORSCAN is the one that SHOULD be used. IMO the Autel scan tools are not that good.

Has your FICM ever been re-built and upgraded?
There are THREE important FICM voltages to check.
I guess you are tuned?

All the parts replacements are crazy, especially the wiring harness replacements - but (as posted above), you didn't say over what time period for the replacements. Replaced in the past year? 20 years? week? ALL those listed replacements AFTER beginning to get the described issues? Also - who did the work the past few times?

How long have you had this specific truck??
Looking at past posts you have had quite the assortment of Ford vehicles ...............1995, 2012, 2022, 2025 Bronco, now a 2003 ,,,,,, and even a Saturn V rocket, lol.
https://www.ford-trucks.com/forums/1...l#post20067451

Simply unplugging the ICP sensor is effective enough at trouble shooting that specific sensor (and of course inspecting the connector and wiring when you unplug it), I can NEVER understand replacement of expensive parts as a guess, but ESPECIALLY that one!

Is the oil level good (MUST also verify it isn't too HIGH)?

 

Start with the charging system and batteries. You don't know how many times I've found a loose battery connection, alternator charging wire loose, or one if not both batteries weak or just plain bad.

I agree with Mark that parts and their packaging can be counterfeited even down to the most complicated detail. This is why I buy parts for customer vehicles from the dealer itself rather than online stores. Yes, it costs more but I know it's genuine and I have recourse if the part goes bad.

 

The only codes I have are for the EGR, which is no longer present.

 

Thanks for the reply!

The last ICP was purchased from SWAG Offroad and there is a FoMoCo and part number printed on the electrical connector portion of the part. It's my understanding Ford no longer makes these? Did I hear wrong? My last IPR came from our local dealer, if it's counterfeit, then I would need to have a talk with them.

Unfortunately, I only have an Autel scanner. I can try to get a Forscan setup going, I will need to order a plug as far as I have researched. My small town doesn't have very many resources available to pick up parts, most online orders take a week or longer.

I have not had the FICM replaced/rebuilt since I have had it, that has been about a year and a half. The truck was tuned but flashed back to factory trying to find out why it was running like it is. I didn't know what tune it had as it came from the previous owner who didn't know either.

The work was done by a local guy, no need to get into all of the who what when where, but it was a mistake, no need to relive that. All of these parts were replaced withing the last 8 months. It started with a failed injector. I haven't been able to drive it reliably since.

I have owned lots of trucks in the past, all fords. I have never owned a new bronco nor would I want to. A Saturn V to send this truck to space is an idea I hadn't thought about LOL!

I am here posting on this forum to try and troubleshoot this myself since the other person is just a parts changer and not a mechanic.

Oil is slightly high, just past the top mark if sitting for a night.

I bought this truck to use as a general/daily use truck so I didn't have to drive the 550 around town.

I did just make a trip up to SLC last week and this time, the issue seemed to be intermittent. No rhyme or reason as to when it would do it other than it is just fine when it is cold. This to me does point to an electrical problem, but I could be wrong.

I hope I have answered your questions, Thanks for helping.

Shane

 

I agree that intermittent problems frequently turn out to be electrical OR electronic. I have a "known good" FICM so that I can confidently determine if a FICM is or isn't an issue. It might be worth a swap if you have access to a known good one. Simply for reliability, I (early on in my ownership) sent out my original FICM for repair and upgrading. I think it was money well spent, I have never personally had a FICM issue. I also have a spare FICM relay as sometimes they get flakey. FICM electronic issues sometimes are not always identified by codes.

Several replaced harnesses raises the question on where they were purchased. and if they might have "issues".

Warren in the past has often times had issues w/ their injectors. This is why a GOOD Ford scan tool is a must. You never know about codes because scan tools like Autel will NOT read all of Ford's codes - especially transmission and some injector codes.

Not that I am a fan of SWAG, but you can somewhat effectively troubleshoot for ICP issues by disconnecting it (and be sure to inspect the connector and the wiring). Ford may have changed suppliers on the ICP sensor, but I have not heard that it has been discontinued from Ford.
https://parts.applefordwhitebearlake...bly-3c3z9f838a

@Toreador_Diesel mentioned getting batteries and charging system in order. Have you done that yet (including cables and grounds)? It is important!

IMO flashing back to stock while troubleshooting this was the thing to do.

The oil level sounds fine, I was asking in case a leaking injector is dumping fuel into the oil. That can cause issues as the engine heats up, but not so evident when cold.

 

perfect lots of folks come to do this

reign in the shop
verify repair


get the Forscan going so you can retrieve live data and codes
Someone can take you thru those steps when your setup to collect the live data

Post a picture top of engine

 

Thanks for your willingness to help!

I will, over the next few days, get the electrical tested. I have ordered a dongle for Forscan so that will be here Friday, possibly earlier.

Here is a picture of the ICP that I bought. Looked like an OEM part.

As far as the harnesses, the first FICM harness I bought didn't

work, but the second did. The OEM engine harness was cracked in multiple places and frayed. I could repair it, but it would take a really long time to take it apart and fix it, especially for how brittle it was. I still have it and I might try to locate an OEM harness but those are hard to find.

 

 

Assume that the ICP is good, but as I said - you can't go by "looks". SWAG has enough bad reviews on YELP that I avoid them. That said, when you can just disconnect the sensor to see if that helps anything, the ICP sensor is a low risk item IMO. Don't get me wrong, a bad ICP can cause problems for sure - even a no-start, but you can simply remove it to see if things improve.

When the engine is acting up, a wiggle test of wiring harnesses is a good thing to consider. I HATE brittle wiring harnesses - simply NO EXCUSE to use materials that cause problems like that. That said, often times the engine has been allowed to get hot, and that initiated the harness deterioration. I watch temperatures (oi, coolant, transmission) like a hawk.

Let us know the results of the FORScan scan.