I posted this in another forum, but I donr know the cause, so I want to see what you all think.

Ok, I just picked up an 04 XLT Lariat 4x4 5.4L with the stock 18's Goodyear tires. I got it from a dealership that my dad works at. It was going to be sent to auction, but I got it before they sent it away. It did not go through the shop, but did get a safety inspection.

Here is the story.

Picked it up on Friday. Drove it home, no issues.

Drove it next on Sunday. There was a vibration from the start. It started at 30 mph. After a mile it was worse at 40. After another mile was worse at 50, and then it was gone.. Drove at all speeds for about 30 miles. No issues.

It sat in a friends yard for about 3 hours. Drove away. Again, there was a vibration at about 30 - 50. Then it was gone again after a few miles.

Stopped at a friends house for 1/2 hour. Drove away.... No issues. After 5 mile, the vibration was back. I was coasting down hill at about 50 mph when I felt it. Then after 1 mile, it went away...

Got home. Let it sit for 2 hours and took it around the block. No vibration...

That was last night. The truck is an 04 with about 26,000 on the stock Goodyear 18' tires. The fronts are about 35% worn, and are worn evenly. The backs are about 50% worn, but have some Cupping/Scalloping on the inside. Not bad, but it can be seen with the naked eye. All the wheel weights seem to still be on. There is only a very very slight vibration at highway speeds. But no worse than any other 4x4 I ever drove.. The truck does not appear to have ever been in an accident. It is still under factory warrenty..

When it vibrates, it is pretty bad. I feel it all over, not jus the steering wheel. The inside echos and the wipers even shake.

Here are my thoughts: A flat spot from sitting? But why only some times?

A bad tire? Broken belt? But why would it go away?

Out of ballance? Dont think it would go away then..

Couldnt the torque converter cause a vibration??

I dont want to get new tires to find it is something else. Any help you all can give me?????

Thanks

 

My first check would be to check the emergency brake, especially if it seems to take very little travel on the e-brake pedal for it to come on. For some reason the e-brake on these, if adjusted too close, will cause a vibration. It may also be detected by the burning brake smell at times.

 

I have 2004 5.4L Lariat Supercrew with original Goodyear tires. Sometimes I start to vibrate @ 20 mph, then @ 40 mph it is unbearable. I stop, then start up and then it's smooth as silk.

Any ideas?

 

If it is from the rear, exactly what I stated on the previous post.

 

It doesn't seem unique to front or back. It seems to shake from the core?
I rarely use the emergency brake, but I've checked to make sure it is off going forward.

I thought the tire(s) might be out of balance, but then the vibration wouldn't go away, would it?

Any other thoughts? Help!!

 

I also never use the e-brake, but had the problem. The e-brake is what I would look at first. There is a TSB for it.