acdiecast

I'm hoping someone can help me nail down this shake that has been occurring for quite a while.

To describe the shake, I would compare it to having 2, if not all 4, of the tires completely off balance. It feels like an up/down shake, sometimes left/right though.

The odd thing is that it isn't always there. It pretty much ONLY occurs at about 59 mph, but you can feel remnants of it from ~57-62 mph. It doesn't matter if it is in Overdrive or 3rd gear, and it doesn't seem to correlate to a certain RPM range as much as it does the speed. I can also feel a slight bit of it at about 45 and 70ish mph.

I have had all 4 wheels balanced twice, and was rotated front/back once in between.

I thought there was a chance it was the U-joints, because the shake seems to go away somewhat if you throw it in Neutral during that speed. The last time I took the drive shaft down to check it out, the joints felt like they may have a slight binding, but hardly noticeable. I would just go ahead and replace them but they are the staked-in U-joints that Ford claims are non-serviceable.

So, let me know if I missed any symptom details, and thanks in advance for any info you might have.

fishnnut15

I am having a very similar issue. Mine truck (04 f150) feels like it's bouncing and going over the rumble strips at low speeds. Although mine starts from 55mph + it is also intermittent. Im changing the drive shaft out on Monday since my u joints were also stacked. I'll let you know if it fixes my problem or not. I've got them balanced rotated and aligned so far and no luck

vintageman

A lot of shakes at or about 45 usually turn out to be COPs or plugs. How long since they have been changed? They do not always throw a code.
Tom

skintback

I've posted about this and there are tons of threads on it, but I've not seen a solution.
I've had the 56-60mph shake since my truck was new (2006). Had tires checked, changed tires, rotors checked, and nothing changes. I saw where someone said the driveshaft could be unbalanced. That may explain why my rear pinion seal has been changed twice.
Pretty common on these models I think.

acdiecast

Plugs were replaced (with Ford's special 'gold goop' that's supposed to limit carbon buildup) less than 10K miles ago. All COP's are OEM, the ones that were on her since the assembly line. How would I diagnose if it is a malfunctioning coil, if it is otherwise performing satisfactorily, and such an isolated incident?

acdiecast

Thanks for all the replies guys, it's a bummer that this issue is so predominant and there seems to be no fix. Any chance it's an imbalanced or bent driveshaft?

F150_Life

I agree with skintback, it's a very common issue for our trucks. I was told originally that it had a lot to do with my tires, so I had those checks and I still get the shake.. it goes away though as I continue to accelerate on the freeway.