2008 Engine Woes

[bigsteve]

Our 2008 Expedition EL (i.e. munchkin transporter) has 148k on it. A few months ago we started having a rough idle/low power. I found a hole in the heater hose dripping coolant on the passenger side valve cover. I replaced the hose and went ahead and changed the plugs (broke 3 - #'s 6, 7 and 8). After doing the spark plug replacement, the rough idle was still there, and there was also a loud popping - if I were to describe it, I'd say it's like putting some bolts inside a plastic coffee can and shaking it really hard - and also no power, but only at 2500 RPM and up and only under load - it won't happen if I rev it in park or neutral.

My scanner is showing a consistent #3 misfire. I replaced the #3 COP and boot with a new one - it was the one that got the brunt of the coolant leak. I swapped #2 and #3 fuel injectors (both looked clean and the ohms were good; I changed the fuel filter a year ago) - no change. I also hooked up a noid light to make sure the FCM was working - it seems okay, but obviously, I can't check it going 50 MPH.

I am looking for a compression gauge that will screw into the 16 mm spark plug holes, so I haven't been able to do that yet.

At first, I was thinking that the popping was the cylinder not firing and passing fuel to the exhaust manifold and igniting there. Last night I pulled the #3 injector harness and ran it down the road and still got the popping. If it was the fuel filter, I'd think it would be on random cylinders, not just #3. I've pretty much exhausted my troubleshooting abilities... any ideas? I don't know what would cause it to happen only under load.

 

[BIG GREEN FORD]

Check the connector Might have corrosion. Run it with #3 coil discounected see if its the same then u know if your connector is working. Also make shour that you are on the #3 cyclinde

 

[stamp11127]

I remember reading something similar to your description, but I'm suffering from CRS at the moment. I think it was mentioned under cam phasers. Might want to search for that and see if it is like your rattle problem.

 

[bigsteve]

Yes... I'm sure I'm working on #3 (unfortunately). Pretty good assumption for dealing with the interwebz, though...

I did the compression test last night - everything looked good... #3 was the lowest pressure (152 psi), but <10% of the highest pressure (167), so I think that's not the issue.

Just for grins, I left the #3 COP unplugged, and still got the same result. I hooked the COP up to one of the plugs I removed a few weeks ago, and got a good spark.

I'll try to find the data on the cam phasers. I've noticed the ticking before - this is definitely worse than that, and only under load... I thought that the cam phasers were pretty much a problem at the full engine range?

Anyone else have any suggestions as to what will cause a single cylinder to misfire and cause a popping noise at high load?

 

[bigsteve]

OK, so if it is a bad cam phaser somehow causing the noise only at high RPM, then if I disconnect the solenoid, it should 'lock' the phaser at the idle timing position, right? If so, there would be no noise (if it's the phasers)?

Would a timing chain or tensioner problem cause the high RPM noise?

 

[bigsteve]

Bad driver side timing chain tensioner. I can feel the play with the valve covers off... we'll see how bad it is once I get the front of the engine off.

 

[bigsteve]

Ok. After changing the timing components (both tensioners had the gaskets blown out... guides and chain looked okay, but I changed them anyway), it still had the problem. Took it to the muffler shop for a backpressure test, and the passenger side cat is bad.
At least now I know...

 

[DRS1]

What crappy engineering the three valve 5.4 is. Your story is so common. And insane the defect rates for this and the plugs/coil issues.

I should check around as a newer member. My owned since new 2003 Eddie Bauer has the 2 valve 5.4. 148k. Never had any engine issues at all. Did I get the luck or the draw? Or is this version more reliable (yes, less power)?

 

[DetroitDarin]

wish I'd read this sooner - classic bad-cat symptoms. Good luck with the fix!

 

[hendricksen11]

Hmm I'm having a rough idle, was thinking pcv/vacuum leak but good to see other options if those don't fix it when I finally get the time to figure out was going on..

Sent from my AT100 using Tapatalk

 

[bigsteve]

What crappy engineering the three valve 5.4 is. Your story is so common. And insane the defect rates for this and the plugs/coil issues.

I should check around as a newer member. My owned since new 2003 Eddie Bauer has the 2 valve 5.4. 148k. Never had any engine issues at all. Did I get the luck or the draw? Or is this version more reliable (yes, less power)?

I've got a coworker who shot a spark plug out of an '03 Expedition while on vacation... They weren't without their problems either... but most modern engines seem to have their quirks. This is the first problem that I've had with the engine in the 4 years/100,000 miles I've owned it. I just wish I'd figured out the problem sooner.