Hey everybody,
This is my first post in the Expedition forum. I just sold my Excursion with the 7.3 diesel and replaced it with a 2005 Expedition XLT with 95,000 miles on it (I didn't want to sell the Excursion but financially it made sense). Any how, I bought the truck used and it came with a 1200 mile warranty. It was throwing a code and the dealer fixed it (intake manifold runner control) as well as fixing my A/C. I am over the 1200 miles by a couple of hundred and today I was driving on the highway and had the cruise control set at 70. Suddenly the car felt like it was losing power and the speed dropped to 60 mph and the engine light started flashing. After about 30 seconds, the engine light stopped flashing and went off and the cruise brought the car back to 70 mph and all seemed good. But it happened one other time on the way home, again for about 30 seconds. Any ideas on what this could be? Can I bring it in and get the code read even if the check engine light is off (can the computer they use tell what triggered the engine light previously)? Thanks for your help.
Ted

 

I helped Ted find this lovely cantankerous Expedition and it really is a nice rig, but it seems to have some "gremlins" to deal with.

Not knowing the 5.4 at all compared to the 7.3.......my only advice would be to hit up an AutoZone or something to have them pull the code (it should be stored for a while unless you disconnect the battery or reset it etc.) and then post the code here so people can help diagnose.

 

Flashing CEL is a misfire. Often it is a coil pack going bad. Do you know if the plugs have ever been changed? Try and get the code out of the computer. It will tell you which cylinder is misfiring. By the way these engines are numbered weird lol.

4 8
3 7
2 6
1 5
front pass side driver side

 

An 05, eh? Better hope it's not the injectors....

 

I got the codes, P0152- HO2S circuit high voltage (O2 sensor)
and P0174- system too lean.

So hopefully its just a sensor. It looks fairly easy to fix, like I might even be able to replace it myself. From what I have seen so far, it's bank 2 which would be passenger side in front of the Cat converter?

Ted

 

Time to roll up yur sleeves and get those stumpy hands in there and give her hell......hopefully it is just an O2 sensor......coil pack would have given you a code for a misfire in X cylinder(s) I believe.....

Hopefully someone who knows the 5.4L will chime in......I'm flying blind a bit ont he 5.4......

 

Coil pack is bad most likely. Once this happens, you will get numerous misfires on different cylinders occasionally. Think of this too, codes trip other codes..

I had a coil pack go bad recently, and it caused 9 different codes to fire off. O2 sensor, inefficient catalytic converter emissions, etc..

I was ready to replace the O2 sensor, (the 5.4 has 3) and possibly one or both catalytic converters. Took it to 3 different run of the mill, good ole boy mechanics with small shops, and none could troubleshoot it. I finally broke down and took it to the dealership the other day and their machine detected the bad coil. Went ahead and had the plugs and wires changed while they were in there and $640 after tax later and the engine is running like new.

The mechanic at the dealership said what alerted him was the catalytic converter message. He said Cats do not go bad on their own. Something causes them to not perform right and this in turn fires off codes from both.

I would take it somewhere where mechs are working on the 5.4 expeditions and such all the time. They will be familiar with every fault that usually comes there way. And can troubleshoot it accordingly, however there labor rates are usually thru the roof. However, the time spent shopping it around could become old quick and end up costing you more.

 

I'll withhold my opinion until we here back about any trouble codes.

 

"I got the codes, P0152- HO2S circuit high voltage (O2 sensor)
and P0174- system too lean."

He has no code for a misfire at this point, so there is nothing to outwardly suggest a coil pack issue.....granted I know they are common.

This one feels lile a straight up O2 sensor issue which would also possibly trigger the P0174 as the PCM is getting a crazy signal from the sensor.

But then again WTF do I know..........

 

Not in front of my engine now but as I recall, the #1 bank is the passenger side, not the drivers side.

Whatever cylinder is the front cylinder in the engine casting determines side #1, which I recall is the passenger side.

Probably not an O2 sensor as it's reading the engine combustion condition.

Check as noted above, a plug, cop, or vacuum leak (egr elbow).

 

You have a misfire on one of the Bank 1 cylinders (passenger side)

 

Personally what I would do is clear the codes and drive around with a scanner in my truck (one that reads live data) and wait for it to happen again. When it does if you turn the scanner on it will tell you which cylinder is misfiring. Who knows though it may not happen again for a long time. Mine misfired when I was on vacation and then didn't miss again for about 8 months. It seems like it has to misfire continuously for a LONG time before the computer will store the code (I drove 2 hours with it missing occasionally and no code, took about 20 miles of missing continuously to set the code). If it starts to miss drive it hard and try to get it to miss as much as you can lol- that's how mine finally kept the code saved. If the plugs have never been changed (or you don't know) I would recommend changing them soon and inspect all the boots for cracks or deterioration on the coil packs. You can buy a complete set of 8 COP's on ebay for less than what 1 costs from the Ford dealer...

 

I respectfully disagree.

1) If you have a code, don't clear it as it should be your roadmap to solving the issue.

2) If your engine light isn't on, it doesn't necessarily mean the code isn't stored. Borrow a OBD tester from your local auto parts store to check.

3) Once you know the condition, you can purchase just what you need, not try the experimental testing process so many use, spending needless dollars.

I do, however agree that new plugs, cop's or cop boots, pcv elbow are probably the best places to look.

 

I would keep track of what codes were set off and clear them to see if they return. If the codes aren't cleared, then you would want to recheck the codes frequently to see if anything new popped up. If the code was stored it would have come up when he pulled the other codes. I'm not implying that he buy any parts- other than plugs if unknown condition. Definitely don't throw parts at it- you'll drive yourself nuts! Though I think we've all been there at some point lol

 

I thought I would post the outcome in case it can help anybody in the future. After I had the code read, I figured I would be able to drive it for a while if it was just the O2 sensor, as I have driven other cars in the past for months with the engine light on and needing an O2 sensor and because my truck had been running pretty well. So I loaded two of my dogs in the truck and went to work and drove about 30 miles and all was well. Then I gassed up and pulled out of the station and the truck would barely accelerate. It seemed to get better so I figured I had best try to get home since it was a holiday weekend. I got on the highway and couldn't get the truck to go over 45 mph. I knew there was a Ford dealer about 4 miles from me and then nothing for about 20 miles, so I limped to the dealership and hoped they could help. I called my wife to come rescue me and the dogs as they thought they wouldn't be able to look at the car until Saturday. But after about 3 hours they asked me to take the dogs out and they pulled the truck into the bay, and 45 minutes later and $235 bucks and I was out the door. It turns out that the dealer that I bought the truck from (or maybe the previous owner of the truck) had replaced the O2 sensor with an aftermarket sensor. The wires and harness were too long on the aftermarket sensor and they left them to just hang there, and they ended up getting hot because it touched something that was hot and melted the wires. They put in a new sensor and its been running great again for the last 200 miles. I am keeping my fingers crossed. Thanks for all of your ideas and suggestions.
Ted