Hello all:
I just signed up here. I spend a lot of time on other web board for my other cars... I've not had many issues with my truck so I've not had much to do. Anyway, noticed a wealth of info and figured I'd join up and see what was out there and if I might contribute any knowledge I have acquired along the way...

So here's the deal. I have a 2000 Expedition XLT 5.4L. It has 114k. It generally stays parked until we need to move a big load or haul something. A fuel sipper this monster is not! She's also topped with a Kenne Bell Twin screw supercharger.

After spitting out spark plugs we swapped the heads for modded ones from a modular shop and they've been great. We also did new t-chains and guides (this was at 103k)

The the TC took a dump so we rebuilt the trans. (110K)

All has been good until a few weeks ago. It just started chugging like crazy and trying to sputter to death. Not one CEL illuminated. Engine chugs on the passenger side like it has bad cam phasers (this is a 2000 so there are no Cam Phasers to my knowledge)

I immediately though the COPs might be acting up. I tested all of them and pulled all the plugs to test them and check their gaps. All good. Frustrated, I replaced the COPs with all Motorcraft units to eliminate that from the equation.

I had a cheap scanner that did not give me any info. I looked through my factory service manuals but that didn't help either. I broke down and bought an AUTEL MD808 Pro Scanner and ran general scan- nothing. Tested mode 6 to see if there was an unreported misfire. Nothing!

I tested the MAF and it's good.
I tested EGR and it's good (only a few years old)
I checked IAC and cleaned it (it has about 10k miles)
I replaced the fuel filter
I had all the injectors cleaned and flow matched
Battery is new and 100% charged

The codes I do get don't make much sense: Both in Key on engine off and Key on engine on

1288-cylinder head temp sensor our of self test range
0505-IAC
1705-transmission range sensor out of test range
0900-clutch actuator circuit open
0072-Ambient air temperature below minimum voltage -40 detected
1318-battery voltage low
1315-battery saver relay coil battery short
0309- cylinder #9 misfire (this is a V-8)

The scanner tells me that what the codes indicate but a google search gives me different info.

I've read till my eyes hurt and watched a ton of video's to see if I could find a truck with a similar sound and issue... (sounds like cam phasers)

Engine will start and run but it's tough to start and tough to keep idling until it warms up. Truck drives but shudders like crazy.
As a side note, I noticed that the exhaust was a little rotten and I replaced it (Cat Back). I had an idea that the factory cats might be an issue and disconnected them. Engine still chugged like mad. While the cats probably do need replacing at some point, I don't think that they are the culprit.

DISCLAIMER: I am not a mechanic. I like to tinker and generally can handle most car issues myself. I'm trying everything I can think of before breaking down and going to a real mechanic. Hopefully, you guys might see something I've missed??

 

I'd pull the plugs and do a compression test.

 

Thanks for the quick response!


UGH. I really hate the design of the engine. I attacked the plugs and coils first to get it over with. Now a compression test?

Would you care to elaborate on why a compression test would be first on your list? I'm curious about all the codes. Nothing I read pointed to a compression test. Engine has been sound, with relatively low miles. Never gets beat on (actually rarely driven). Did fresh stage II heads 11k ago- Cannot fathom that something would be wrong in there...

Again, since I'm not a mechanic, I like to try and understand this stuff.

 

Superchargers can burn valves and cause other damage if the PCM is not properly tuned.

 

Interesting. That supercharger has been on since 2001. Installed and tuned by Stillen in SoCal. I think, at best it may push like 6-8 lbs of boost.

Aside from a compression test are there any less invasive options?

I have the compression tester and now have it on my "to do" list.

 

Any other ideas aside from the compression test?

 

Given all those crazy, off-the-wall codes (Cyl 9 on V-8), other things 'out of range' ??:, have you considered a flaky ground or poor electrical connection.


An inexpensive effort with practically zero downside might be to disconnect both battery connections, clean PCM connectors real good and remove / burnish and clean every ground connection you can find, then reconnect everything.

A poor ground or electrical connection will drive any computer NUTS.
Just a thought.

 

It's a good thought. (I had that happen to another car and it was a tiny bit of scale on the PCM that needed cleaning)
It's one of the first things I did when this problem appeared. (I neglected to mention it.). Everything was nice and clean and good to go.

 

If you live anywhere where they salt the roads a corroded ground would make total sense.

 

Yea, you need to do a compression test on that Cylinder 9. --- Just kidding.


Forgive me. I looked back over all the posts and that just hit me. I do not have any more 'decent' ideas.


Have you made any progress.

 

GLC was closest. We stuck a camera in cylinder 1 and found the issue immediately. The valve seat was coming loose. It jammed the valve and the rocker popped off! Pics posted as this may help someone in the future. Head is at the machine shop for assessment. I will follow up when I have more news.

 

Fixed! New seat, valves and valve job all the way around. Installation begins today!