New 2001 Expedition AWD Eddie Bauer 5.4L owner with Shuddering at 40 mph

[1955moose]

Isn't it amazing in over 40 years of messing with cars/ trucks, I only had 2 coils ever go bad on me where I had to replace them. We used to change spark plugs/ points every 6-10k. You could run them out to 20k if you didn't mind a little drop in power. These days with coil over plug, the so called improvement in design, were chasing our tails, changing out coils, plugs, boots, springs. All within 80 k . Ain't it amazing what garbage they throw at us, and say buy me, new and improved.


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[BTVelocity]

Finally threw a code.....again! P0171 System Too Lean Bank 1

So I finally got a code while shaking/shuddering at just under 50 mph, about 1200-1300 RPM (I'm guessing OverDrive). It's one of the same codes I had prior to all of the engine items I replaced.
P0171- System Too Lean Bank 1. Can this code account for all this shaking/shuddering between 40-50 mph?
I have all new plugs, coils/boots/springs, fuel injectors and fuel filter. Fuel rail pressure was checked and within Ford specs. I've sprayed the hoses and intake manifold areas with Brake Cleaner with engine running and could not get the engine to choke.
Any suggestions on how to diagnose and repair the P0171 Lean Bank 1 condition?
stamp11127: yes, the new coils included new boots/springs, and they were even primed with dielectric grease in the end of the boot. Thanks for the advice on the inner wheel well access to the exhaust ports. I'm going to try tightening the Harmonic Balancer bolt 1st, and take it from there.

Thanks, all!

 

[1955moose]

Try swapping coil on number 1 to 2, see if code swaps. Also just for ha ha's buy 1 new spark plug for # 1 cylinder, clean threads, the smallest thing makes these SUVs misfire. It could have a crack in the plug porcelain !


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[1955moose]

If after playing around with coils and such, the only item you didn't change, and it's a maybe. Change the front
Oxygen sensor on passenger side, that will trigger a p071 code. Use a Ford part if at all possible. The other brands are hit and miss. If the o2 sensors are old this is another possibility to your rumble problem.


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[BTVelocity]

The misfire codes are back!!!

I decided to go with stamp11127's advice and use the PCM to help me diagnose my problems. I've hardly driven my Expedition due to the awful shaking at 40-50 mph. But I've driven everywhere over the past 2 days.

In the last 24 hours of driving, the codes for 'Misfire Cylinder 4 and 7" have returned. I'm now carrying my OBD II with me and have cleared the codes about 8 times in 24 hours. The codes show up either instantly when I turn on the engine, or within a few minutes of driving. Just before coming home tonight, the moaning noise came back again on start-up (it was then that I realized I hadn't heard it for several days) and the codes that I cleared on arriving home were the 'Misfire Cylinder 4 and 7," as well as "System too lean bank 1." So I am now convinced that the moaning noise is an intermittent vacuum leak somewhere.

The annoying thing is that the night I bought the vehicle in September 2015, I ran by AutoZone and they pulled the same codes I pulled tonight, "Misfire Cyl 4 and 7, as well as the "too lean Bank 1" condition.

So after new plugs/coils/boots/springs/fuel injectors/fuel filter/PCV Valve, I'm right back where I started.

One thing I've left out of my Expedition's history is that when I changed the plugs, Cyl #6 had a short threaded insert that came out attached to the plug. Cyl #7 had a really long threaded insert attached to its plug when I removed it. It also looked like the long insert (Cyl #7) was installed backwards, so I flipped it on re-installation. I used my Harbor Freights inspection camera to look at all the other threads before re-installing each plug, and no other inserts were seen.

I had swapped some of the coils early on, but the codes seemed to always stay with #4 and #7. I also checked for a spark from the coils for #4 and #7 using an old plug, and they sparked well. Now, of course, I have all new coils....

I don't mind swapping some coils again, but now I'm starting to worry that my problems with #4 and #7 are in the cylinders.

What say my Expedition friends?

Thanks!

 

[1955moose]

Well you've gone this far, how bout a compression test, especially on the dtc code cylinders. It's like bad health, you don't but you do want to know!


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[BTVelocity]

Compression Tests

Moose:

You are exactly right. I knew that cylinder compression tests were next on the list, but I just didn't want to go there if I could avoid it.... (yep... "like the medical test you don't want to do, but you know it has to be done" --- great analogy, Moose!)

Good news is that I've got a friend who has the compresion testing equipment and is willing to help. Some day next week (warmer temps) I will remove all the coils and plugs and then call my friend in for the compression tests.

I'll let you know what I find.

Thanks!

 

[1955moose]

Cool, hope your checkup go's well with the Doc!


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