Still getting adjusted to my old/new Excursion as I bought a few months ago. It didn't seem to do this when I first got it and now it does or it's gone from barely noticeable to more noticeable. I haven't changed anything on it yet to affect this mechanically. Around 1300RPM to 1800RPM, I get a vibration happening. Sometimes it starts at the stoplight very subtle and slow when I let off the brake, then comes on more stronger and faster in those ranges. It just feels like the truck is vibrating. When I let off the gas it stops. Transmission or after that in drive line? Help me know where and what to look for to narrow down please.

 

Check your driveshaft joints and tire balance

 

^^^ Tire balance was my first thought also

 

Wouldn’t tires continue to vibrate regardless of accelerator pedal and RPM range?
im thinking I’ll check those driveshaft joints for certain. Seems like a likely culprit there.
Is it possible transmission issues?

 

Drive-line seems likely, check the splined slip-joint in the driveshaft. Transmission could be contributing as well. I found out mine was the last source of my vibrations when it was opened up for a rebuild. The input shaft bearings at the pump if I recall were shot and most were missing.

 

Pretty much all of the above.

Plus can't rule out tie rods, ball joints, warped rotors, loose sway bars.

While it may be transmission related not likely as you didn't mention any shifting problems or snatchiness.

Another possibility: Is it actually a physical shudder in the wheel? These things are notorious for heat shields around the exhaust vibrating, clanking, rattling. Especially at low speeds or under acceleration.

I'd start with the cheap easy fixes first. Balance the tires, try different tire pressures and grease all the fittings around the truck. Check your lug nuts. Simple stuff to start narrowing it down.

Good luck. Keep us posted.

 

I’ll see if I can check some stuff today. Going to get damn cold here in single digits and snow later today so it will hamper my progress here.
There is a physical vibration in the whole truck when it does it the worst. So bad the mirrors shake and you can’t see clearly out of them.
Also, just had all the steering checked at the shop and they said it was in great shape. They said I need brakes though. Looking at better aftermarket options now. Can’t see how those would cause vibration under acceleration but I’ll get to those eventually too.

 

Driveshaft felt fine in the u joints. Both front and rear had no play. However. The spline slip joint in the rear was missing rubber boot. It had the crimp rings that once held a rubber boot in place but it was long gone. Does this slip joint look ok? Kind of dry if it needs grease.

 

I would pull that out, clean it up, pack it with grease and put on a new boot.

 

Mine has just started doing this today It is very pronounced at 55-65mph. I will be checking all the joints (U, Ball etc.) see what's causing this. Have to wait a few more weeks though as the temps up here in VA aren't getting anywhere above freezing for a while

 

So, I’ve had some things evaluated, I am in need of breaks and a worn draglink. Everything else is in good shape. While I don’t think it has anything to do with brakes because it starts doing this shudder or vibration at idle when releasing the brakes.
doing some reading, I’m curious if it could be a torque converter shudder. Anyone ever get a shudder at certain RPM’s from torque converter or transmission? Because it is RPM significant and stops when I let off the gas, I’m convinced it’s in drive line somewhere. Or yeah, when I rev engine in neutral it’s not doing it from engine.

 

Yes, that can certainly be a cause. That blue stuff is actually a teflon type of coating and it looks like yours is mostly worn off. Pull it out, grease it up, put a boot on it, and check the u joints while you have it off. Also, leave the rear driveshaft off, put the truck in 4wd and go for a drive. If the vibration is gone, it was definitely coming from the rear DS.

 

Thanks for the advice.
couple more things recently. I just had it at transmission shop to get serviced. Drop pan, new fluid and filter and inspected things. All good there and they said it looks great. They also said driveshaft looks good. I’ve also inspected my u joints myself. Transmission shop hooked it to a scanner and said it’s a misfire on cylinder 3 and that’s causing the vibration. So I changed coil and plug tonight and maybe a little smoother but same vibration issue. Especially around 44mph and about 1300 rpm. It is really noticeable there. I guess I’m going to have to do driveshaft next.

 

I am also in the exact same situation, and a specialist transmission shop diagnosed this as a misfire too and claimed that the entire bank 1 had bad injectors causing several misfires but wouldn't show me any proof of that happening. This is after all coils and plugs were replaces just last month. My vibration issues started after all this work was done and I had driven the truck over 800 miles.

 

Dang - sorry to hear that! My vibration issues started after an oil change and once over by my fleet mechanic. The only thing they did besides oil change was rotate tires. There is no way this vibration is from tires. Reason being is how it responds to throttle and it is seemingly getting worse while just sitting and idling a little rough. The RPM's don't stay steady when it's idling, not quick jumps, but unsteady and has a bit of an engine vibration when sitting still. This is telling me more and more it's coming from the engine.
I was wondering if I need to inspect fuel injectors next after replacing the alleged bad cylinder 3 coil and plug. Anyway to test coils without expensive scanner?

EDIT: did a scan from my BlueDriver bluetooth scanner. Not sure if it can pick up misfire codes, but it had none. It did pick up these relevant codes though: P0460 Fuel Level Sensor 'A' circuit, B1201 Fuel sender circuit failure, B1203 Fuel Sender circuit sender. Makes me think there is a fuel delivery problem to the injectors possibly causing a misfire. If it's still running rough and vibrating, would I get misfire codes?