2006 Expedition- Need help shops can't figure out the issue

Mr_Kostas · May 9, 2022

Jlh8485 said:
This all started with it having an issue wanting to crank other than that it ran fine and no light was on. In the past 6 months we have replaced a lot of parts and had a good bit of work done (I will list below). The issue we are having now that I and two shops couldn't fix is that when you go to accelerate to pass or get out on the highway to merge is that the check engine light starts blinking and then stays on and at the same time it's popping back through the intake (not spark knocking) I want to sale it due to how many issues I have had with it but don't want to do so with it still having this issue. There has been different codes that came up but some go away but the main one that keeps showing is a misfire on cylinder 3. Now there are two more codes that came up after getting it back today plus the misfire code. The shop said only other thing they could do is put autolite spark plugs in it because they read these motors have issues with a certain spark plug but it has motorcraft in it they also said that was no guarantee and that it was running fine now but on the way home we see it's got the exact same issue. We are at a loss now. Any advice?

Parts and things done:
New spark plugs
3 new coils, cylinder 3, 7, 8
New fuel pump
New fuel and air filter
New fuel rail sensor
Oxygen sensor
Throttle body assembly
New spark plugs were cleaned by 2nd shop
Combustion chamber cleaned
Exhaust checked for back pressure
Compression test
High pressure fuel rail sensor

Suggest to try going after the P0303 first.
Stick with the Motorcraft SP-479 Spark Plug and cant go wrong. Make sure the are gapped at .34 or so.
Swap #3 coil and plug with #1 coil and plug.
When removing coils and plugs make sure there is no coolant in the spark plug well
Run engine and see if error comes up again, see if it is still on #3 or it moved to #1
MIL blinking and staying on is an indication there are many faults but after so many the MIL will stay on, so blinking then full on is a normal indication of a fault
Try getting an ELM327 Bluetooth adapter (ebay) under $10 and download on your phone the "Fordsys Lite" app.(free)
Pair it with the ELM327 adapter and look for the faults.
You can clear the faults on demand as needed.
Also use a can of "Seafoam" ( Wallmart/Menards/Autozone etc) in full tank of gas
Let me know wheat you find

Jlh8485 · May 9, 2022

Wegner44 said:
You’ve only replaced 3 of the coils… how old are the remaining 5? I chased random misfires until I changed all the coils. Now it runs perfect. That would be my first go to. I also bought a $90 code reader and kept it with me so I could diagnose at will. That has saved me hundreds of dollars by not having to go to the shop to change out sensors or coil paks or anything basic you can do at your home.

Hope View attachment 73381this helps!

Thanks so much. We have a set of coils coming today so we are going to change the other 5 and see if that does it and then if not check out what others have said on here. All the help is greatly appreciated. Don't trust dealers or any shop for that matter so this forum is really helpful. Thank you!!

texasscot · May 9, 2022

My latest cylinder 3 misfire episode began after I changed the plugs but it was due to the plastic connector to the injector falling apart due to heat degradation over time. The electrical connector no longer fitted tightly in place. This is maybe less likely in your case as you’ve much lower miles than mine (248k). Solution for me was to get a bag of connectors and solder a new one in. This is not a lot of fun owing to the short wires and location but it fixed it.

SafariGoneWrong · May 9, 2022

My 2006 XLT had similar symptoms 8 years ago at 80K miles but without the vapor purge problem. Had power issues under load and got a cylinder 5 misfire code and occasionally the blinking check engine light. 8 Autolite HT15 plugs fixed the problem. I should have done plug boots at that time and will do those later this year with new plugs, but Motorcraft this time.

Highly recommend getting an OBDLink MX+ OBD2 Bluetooth Scanner ($139.95 from Amazon) and downloading Forscan Lite on your smart phone. I use my phone as a 2nd set of gauges when driving; usually looking at short and long term fuel trims, O2 sensor voltages, VCT cam position and error, VCT solenoid duty cycle, misfire counts and more.

Johnathan M · May 9, 2022

If cylinder 3 is misfiring, then obviously there’s a problem with that specific cylinder. You said you changed the plug and coil on cylinder 3. When you changed the coil, did it include the boot/spring between the coil and spark plug? It’s also always possible to have gotten a bad coil. You could swap the coil on cylinder 3 with one from another cylinder that is not misfiring. See if you still get a misfire on cylinder 3. If you do, then you will definitely have ruled out the coil. You could also check your wiring to that coil. If it’s not in the loom and has a crack in the sheathing, it could be grounding somewhere and causing the miss.

I strongly agree with the suggestion to get a code reader. You can check for misfires without taking it to a shop. But you can get a Bluetooth code reader that connects to an app on your phone for $30 or $40. This is what I use and it works great!

Veepeak OBDCheck BLE Bluetooth OBD II Scanner Auto Diagnostic Scan Tool for iOS & Android, Bluetooth 4.0 Car Check Engine Light Code Reader https://smile.amazon.com/dp/B073XKQ...i_i_5518THDB8EMAXJ5M9ZDJ?_encoding=UTF8&psc=1

mbtech2003 · May 9, 2022

Mr_Kostas said:
Suggest to try going after the P0303 first.
Stick with the Motorcraft SP-479 Spark Plug and cant go wrong. Make sure the are gapped at .34 or so.
Swap #3 coil and plug with #1 coil and plug.
When removing coils and plugs make sure there is no coolant in the spark plug well
Run engine and see if error comes up again, see if it is still on #3 or it moved to #1
MIL blinking and staying on is an indication there are many faults but after so many the MIL will stay on, so blinking then full on is a normal indication of a fault
Try getting an ELM327 Bluetooth adapter (ebay) under $10 and download on your phone the "Fordsys Lite" app.(free)
Pair it with the ELM327 adapter and look for the faults.
You can clear the faults on demand as needed.
Also use a can of "Seafoam" ( Wallmart/Menards/Autozone etc) in full tank of gas
Let me know wheat you find

Are the sp-479 plugs for the 3-valve. Shouldn’t they be sp-546??

texasscot · May 9, 2022

I just put motorcraft sp-479s in my 2003 5.4 2 valve if that helps. I also just left the gap as supplied. Runs fine.

Danielgaryhillsr · May 10, 2022

Cam phasers

mbtech2003 · May 11, 2022

texasscot said:
I just put motorcraft sp-479s in my 2003 5.4 2 valve if that helps. I also just left the gap as supplied. Runs fine.

He has a 2006. So thats a 3 valve. Totally different plug.

CountrySplatt · May 16, 2022

From what I have been seeing, there are a lot of issues with the coil packs being just garbage the last couple of years. Swapping the coil packs around cylinder 3 and testing, is the best advice I can see. After that, the 2 valve is VERY well known for cam phaser issues as low as 30k miles. The oil sending unit doesn't generate enough pressure to push the oil to the top of the engine when cold and it causes uneven wear on the cam lobes and spun bearings when the phasers fully fail (best case). Not usually a misfire event from what I have seen, but if it is worn unevenly, you can get some weird timing issues. One video I watched, is to pull the oil pan completely off the engine and look for pieces of plastic in the pan...

Good luck!!

2006 Expedition- Need help shops can't figure out the issue

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