Ford Expedition shakes

[thecoolnessrune]

I will say that Expedition and F-150 Shakes were pretty common in that year range with the 2 Valve and especially 3 Valve designs. I pinged my brother heymrdj as he has a lot of knowledge on the Second Gen Expeditions (2003-2006) as we co-owned one in our college days.

The rear differentials could cause these shakes at around 55 but since it's happening at idle I think it can be ruled out.

Another thing that was known on these designs was the COPs (Coil On Plug). These sit on top of your spark plugs and turn the 12 Volt battery voltage to the ~20,000 Volts needed for your spark plug. On the Expedition these can "fail soft". As in, instead of failing completely, causing a misfire, hard engine shuddering, and a check engine light, they can fail soft, where they still function but in a highly degraded fashion, causing that rough idle and other shakiness that can happen at various RPMs (55MPH is not too far away from where the Expedition shifts into Overdrive, which puts RPMs not too far from idle).

If one COP were bad, it's usually best to replace them all.

Some other posters noted to check your spark plugs, but I don't recommend pulling them yourself. These Triton modular engines used a 2-piece plug design. If you're on the original plugs, these engines have a high risk of the plug breaking off. If it does, you're dead in the water until you can get a special plug extractor to pull the broken plug out of the engine. You'd also need to need to check the chamber to make sure pieces of the plug didn't fall in. It can get to be a pain in the rear. So if you're not sure the plugs have been replaced in the vehicles life, and it comes down to checking those, I highly recommend taking it to a mechanic.

 

[heymrdj]

Got the message bro.

Being a heavier truck, there are lots of things that can cause a shake. Can you describe the shake? Does the vehicle become hard to keep in a straight line (side to side)? Or does it continue to travel straight but it's more of a jarring ride, like rumble strips?

Shaking during start was alleviated by changing the plugs. My plugs at 90K on them when I changed them and they were toast. New plugs made a big difference. At about 127K I had a COP soft fail, and that caused shaking at higher RPMs until it finally lit a check engine light.

Shaking at start can also be because of a bad starting mixture. Frequently we see this in the Triton engines as the valve stem seals start to wear away and allow oil to run down and into the combustion chamber while the vehicle sits (like overnight). The next morning you're greated with a small cloud of blue smoke when the truck starts up, and it stumbles a bit as that oil is burned off. This is typically not something to really worry about until it gets really bad.

I also had shaking and power problems from too much ethanol in gas. I found that stations that offered no ethanol gas made the truck run much better. I also got the same affect by running an ethanol booster sold in the marine isle for boat motors, which frequently can't handle any ethanol.

Sadly for issues like this you really need diagnostics, and if you can't diagnose it yourself, that requires a professional.

 

[Fenixgoon]

Don't forget bushings in the suspension!

 

[sejc]

Are there any warning lights on, on the dash?

There are no warning lights at all. Once the truck is on it shakes and every time I turn it on it shakes the same. the only time it shakes when I'm driving is when I go 55+.

 

[sejc]

Thanks guys! my truck has 140k when it shakes the steering wheel shakes like crazy and doesn't swerve. I have to have a good grip on it so it doesn't shake as much. Now the spark plugs were changed and we also had changed the joints. I just want to get this problem fixed. I only drive it around town and try not to get on the freeway.

 

[sejc]

oh and there are no light on the dash.

 

[heymrdj]

Thanks guys! my truck has 140k when it shakes the steering wheel shakes like crazy and doesn't swerve. I have to have a good grip on it so it doesn't shake as much. Now the spark plugs were changed and we also had changed the joints. I just want to get this problem fixed. I only drive it around town and try not to get on the freeway.

I'm fairly certain the two shakes are different issues and sources. Have your tires been road force balanced? It sounds like a tire is bad. Instead of balancing the wheel and tire by themselves, the rfb applies 1400lbs of force to the tire to simulate a vehicle riding on it. This normally points out either improper balancing or a tire that was made improperly at the factory. I had one new tire cause a shimmy on my expedition, a set of Michelin LTX MS/2 tires. It shimmied pretty bad at 65, the rfb found it, the tire was found to be out of spec, and they just simply ordered a new one and replaced it. No issues after that.

As for shake on start, how long is it lasting. A stopwatch accurate timing would be good to give.