2006 5.4L
Currently has 123,000 miles.
Replaced all 8 spark plugs and 3 COPs at 85,000 miles.
Transmission was rebuilt at 75,000 miles.
#4 COP replaced 500 or so ago.

Over the past 6 weeks, I've had two issues come up:
1). Truck skips at WOT (it may skip at other RPMs but WOT is the only time I notice it).
2). When going 45-50mph, on a flat road or a road with a slight incline, if you get on the gas pedal fairly lightly the truck starts jerking and shaking until the trans downshifts (or if I let off the gas).
3). There's an "exhaust leak" sound coming from the passenger side of the engine compartment that's very noticeable when getting on the gas as described in item 2, and you can REALLY hear it if you're traveling beside another vehicle or a retaining wall along the road.


I took it to the shop and mentioned all 3 issues, and the mechanic rode shotgun and witnessed everything (keep in mind, the check engine light hadn't come on despite the issues). The biggest concern was item 2 and we dropped it off at a transmission shop............they ran tests and confirmed the trans was ok, but found a skip on the #4 cylinder. The mechanic replaced the #4 COP but the problem was still there (jerking and shaking as described in item 2). Took it back to the shop a second time (again, with no check engine light) and they replaced the cam positioning sensor (or cam solenoid?) on the passenger side. Picked it up from the shop and the issue is still there. Without the truck throwing codes, all I know to do is replace the (4) coils that have yet to be replaced. I've read alot on here about people experiencing the same "jerking and shaking" at 40-50mph, and having a "low grade misfire." So, I'm hoping that replacing the other (4) COPs will solve items 1 and 2.

As for item 3, this all started when I was pulling a 7,000lb camper back to Atlanta from Talladega. It started all of the sudden and it sounds like an exhaust leak coming from the passenger side of the engine. The mechanic said they leak tested the manifolds and both passed......so nothing else was really done to fix the problem, and so now it still exists. Like I said above, it's very noticeable when the engine is under load (45-50mph in overdrive and barely pressing the gas pedal) and when something is beside me to where the sound can bounce back towards the truck. I don't hear anything when I'm revving it up in my driveway. I discussed this again with the mechanic this morning and he mentioned something about it possibly being an EGR leak? If the manifolds were tested an passed, what else could it possibly be?

I'm at a loss here and all I've been doing is dumping $$$ into it, trying to get these issues fixed, with no luck at all. Can anyone shed some light on this? I know others have experienced the same issues as me and am curious as to what was done to resolve them.

I appreciate any feedback! Thanks!

 

You might want to purchase a cheep scanner yourself. Harbor Freight sells really cheap units that work. 30 bucks or so. Attempt to pinpoint the misfiring cylinder. The cell won't fully illuminate, it will blink then shut off. So you COULD overlook that.

What I would do at this point is drive the truck, accelerate normally until you come to the engine load where it misses the most. Hold at that position making it miss as much as possible. Push the engine at this load, then coast back to it, -push it again, back down, hold , repeat...

What your attempting to do is increase the misfire count. The misfire monitor will pick that up once the count threshold is met, then forward a blinking cell. Once the cell blinks, you have a DTC in the KAM (KeepAliveMemory). Use that cheep scanner to retrieve data pointing you to the bad cylinder.

Diagnostics aren't cheap at the dealership, -like $100.. The above is something you do yourself to avoid that cost. Also, Auto Zone scans for free, -if you can't find a cheap scanner.

 

BTW- What's up with that exhaust leak ? That model year doesn't normally have a problem like that. - The older models have. In-fact I hear them all the time, when they're next to me at a traffic light lol.

Well, that's a fun one to fix, but you can do it. You'll need to inspect your transmission mount. This is what caused manifold problems/leaks in the past.

EDIT: I can save you time and $$$ if you want to fix that. I've done a few in the past, learned the hard way at first lol. That's if it is indeed a manifold leak.

 

Well, I called the shop earlier today and told them to purchase 4 new coils. Tired of f'n with the thing so I decided that was my best chance of fixing it since there were 4 COPs that have yet to be replaced. Went to the shop today at lunch and replaced the 4 COPs myself. Drove it back to work and all seems just fine.............with the exception of the exhaust leak.

The exhaust leak noise just drives me up the wall since I'm OCD about wierd noises in the cab, and knowing the fact that my truck hadn't made that noise up until just a few weeks ago.

 

You sure the noise isn't a loose spark plug?

 

Funny that you mentioned that, because I questioned the same thing. Could be a possibility I suppose...?

 

Pull the cops and retorque the plugs to 25 ft/lb.

Make sure you use some dielectric grease when reinstalling the cops.

 

Hey I experience the same sort of "ticking" noise like that once it drops into 4th at highway. I did some research and found out our 3v engines are "supposed" to do that and considered to be a normal operating characteristic. Mine also is VERY noticeable when, let's say, going through a drive thru against a building? It's a loud clacking sound but no harm is ever done. I may get some weird looks from people who hear it but that's just the nature of the beast.

 

OH and I also experience a skipping at WOT. It makes my truck sorta jerk and sounds like a backfire noise. I never like to go WOT as a result because i'm afraid i'm damaging the engine somehow. Now I never go above 3k rpm.

 

I would pull the plugs on the passenger side and inspect. I've seen a broken plug cause exactly as you discribe.