I took my 2005 Ford Expedition to the dealership because it’s been running rough, losing power, and sometimes stalling. They ran diagnostics but couldn’t pinpoint the problem.
No check engine light, and they claim there are no stored codes. They said it might be a fuel issue or ignition problem, but they’re not sure.
Has anyone dealt with something like this before? I don’t want to throw parts at it if the dealership isn’t even confident in their guess.
Former Ford tech here (worked from 2004-2011). I’ve seen this engine more times than I can count. If your Expedition has the 5.4L 3V, there are a few common issues that could be causing this.
Spark Plugs – These engines use a two-piece spark plug design that’s notorious for breaking apart and getting stuck in the cylinder head. If they’ve never been changed (or were done incorrectly), they could be misfiring without triggering a CEL. I’d replace all of them first. Be prepared for extra labor costs if they break during removal.
VCT (Variable Cam Timing) Solenoids – If the solenoids get clogged or fail, the engine timing can get stuck in a bad position, making it run rough or even stall. Sometimes they don’t throw a code right away, but you might hear a rattling noise at idle.
Timing Chain Tensioners – If the truck has high miles and hasn’t had good oil changes, the timing chain guides and tensioners could be failing, causing poor performance and hesitation. Again, this won’t always throw a code immediately.
I’d start with the spark plugs and go from there. Good luck!
@Vere
I’ve been looking at getting an F-150 with the 5.4, but I keep hearing horror stories about the spark plugs. I saw that Lisle makes a tool to extract them, but you mentioned an epoxy-based method. Is that the better option?
@Niko
What year F-150 are you looking at? If it’s a 2008 or newer, you’ll likely have the updated cylinder heads that use revised spark plugs, which are much better.
If you’re dealing with the older two-piece plugs, Ford’s official procedure is to crack the plugs loose, soak them with a special penetrating oil (PM3), and slowly extract them. It works about 50-65% of the time. If they break, the epoxy-based Lisle tool is the best way to get them out without pulling the cylinder heads.
@Vere
Do Ford techs groan every time they see one of these come in for spark plugs?
Ezri said:
@Vere
Do Ford techs groan every time they see one of these come in for spark plugs?
Not really. The guys who don’t know what they’re doing freak out, but if you follow the correct procedure, it’s not that bad.
Ford actually has a factory procedure that works most of the time, but if the plugs break, we just use the Lisle tool. Definitely a pain, but nothing a good tech can’t handle.
Spark plug issues on these trucks aren’t always consistent, but if they’re failing, you should at least be getting a check engine light. Are you sure the truck still has its original plugs?
Also, just because the check engine light isn’t on doesn’t mean there aren’t stored codes. Have you tried scanning it yourself or taking it to a different shop?
To me, this sounds like the torque converter is on its way out.
I have a 2010 F-150 with the 5.4, and I had the exact same symptoms. Sometimes rough, sometimes fine, and it was driving me crazy. Turned out to be bad spark plugs. As soon as I changed them, it ran perfectly.
I’d take it to a good independent shop and have them check the plugs first.
Before throwing parts at it, do a compression test. If there’s a major issue (like a failing valve or worn rings), it’ll show up there.