Hello all!

With my running board project on hold, I'd like to ask for your advise on a vibration issue.
2003 Navigator, 181k. It vibrates over 35mph. It is REALLY noticeable over 45.

I have changed tires, balance, rotate, and alignments. It still persists.

I will try to describe it to my best..
1. it only happens when vehicle is moving. I can't get it to do in park.
2. I feel like it gets drowned over 50 mph. Letting the pedal go would decrease RPM, and as the speed gets close to 45, vibration will be apparent, and change in the same pattern as the speed was increasing.
3. I don't think I feel through the steering wheel. it is not shaking left and right. I feel like the whole car is shaking.
4. interval: it is a fast and consistent throughout the speed. I don't think the interval changes with the speed, just the intensity.

I dropped off at the shop this morning and they just called me with the following:
1. engine misfire (I slightly notice it in idle, but I would think it'd change with RPM if it was the misfire)
2. left rear tie rod is loose (the alignment shop did not tell me yesterday -- confused!)
3. rear tires tread is low. (same vibration before and after the change..unrelated?)


Thank you!

 

update: The shop insisted that we start with new plugs and coils as it was misfiring. I had motorcraft plugs and coils int he back of the car, so I told them to replace them.
About an hour later, they called and told me that coil #2 is wet with oil and suggested a valve cover gasket replacement.
I told them to proceed without the gasket and keep the existing coils. For now, I want the vibration gone -- I wanted to spend money in the right direction.

Any input you could give me would be great!

 

To your point, keep your COP's. I would keep as back ups although not sure you really need to change any or all of them.

The number 2 cylinder is pretty easy to change yourself if necessary. If there is fluid in the plug hole, I'd suspect antifreeze, not oil. I would expect more oil on your engine and the floor if a valve cover gasket. The COP seals pretty good on top of the plug hole and if it's that bad, you would easily see a mess around that COP. I bet not the case. See the many posts of antifreeze issues with coolant passage gaskets on the intake manifold.

Not sure I also understand...

Did you replace your tires with bald ones? Not a good way to check for delamination.

Tie rods on your rear wheels? 4 wheel steering?

If this is what your mechanic is telling you, you might look for another before going too far here.

 

Yes -- definitely keeping COPs. If it is antifreeze, what am I looking to replace? Intake manifold gasket?

Not bald -- used tires with more treads. The frequency and pitch stayed the same. It made me think it wasn't the tires?

I was told later that the tie rods are loose, but not loose enough to pose a safety concern yet.

 

another update!

After changing the plugs and coils, they were able to locate the vibration. They found that the front U-joint was loose intermittently. It was ok the other day, but now they see it loose. I asked them to change both front and rear joints.
Does this make sense?

 

U joints usually are either good or bad but not good intermittently. You might have them lube the splined shaft going into the tranny/transfer case first as these dry up and can shake the truck.

U joints would be next.

 

It makes sense only if the vibration is there when moving. When sitting still or idling the u-joints are not moving and cannot cause vibration.

 

I agree with you. I took it as "oh we missed it."
Will the splined shaft get lubed in the process of replacing U Joints?

And yes. The vibration was only when the vehicle was in motion with no apparent relation to RPM.

 

He didn't state what engine he has in that '03, but I'm guessing it is the VIN R engine. A bad seal on the valve cover o-rings will let the spark tubes fill up with oil on the VIN R.

It's an '03 so it has toe rods in the back - the ends of which look like tie rods.

The misfire vibrations were probably masking the u-joint vibrations.

 

You've guessed correctly. It is 5.4L vin R engine. So I am looking at valve cover gasket with the grommets?

 

update: The vibration is gone - I have asked to change the plugs and coils, and change the U joints. It is running much smoother and I am happy.

However, here is what the paperwork says:

* REMOVE AND REPLACE IGNITION COILS AND SPARK PLUGS. #6 IGNITION COIL WAS BROKEN OFF IN THE SPARK PLUG TUBE - REMOVED AS MUCH OF BROKEN COIL FROM TUBE AS POSSIBLE, BUT WAS STILL UNABLE TO ACCESS SPARK PLUG FOR REMOVAL (#6 SPARK PLUG WAS NOT CHANGED). TEST DROVE AND RETESTED AND ENGINE MISFIRE IS GONE AT THIS TIME.

*TECHNICIAN'S COMMENTS: WHILE REPLACING SPARK PLUGS AND COILS TECHNICIAN NOTED SOME VACUUM LINES BROKEN IN ENGINE COMPARTMENT. ENGINE HAS MULTIPLE OIL LEAKS. EXHAUST MANIFOLD CROSSOVER PIPE IN POOR CONDITION. VALVE COVER GASKETS AND TUBE SEALS. LEAKING OIL - CAUSE OF IGNITION COILS BECOMING OIL SOAKED AND CAUSING MISFIRES.

* REMOVE AND REPLACE FRONT U-JOINT ON FRONT DRIVESHAFT

* TECHNICIAN'S COMMENTS: REPAIRED ALL VISIBLE VACUUM LEAKS OTHER THAN THOSE AT THE EGR PRESSURE FEEDBACK SENSOR (CUSTOMER DECLINED REPLACING SENSOR). TEST DROVE VEHICLE AFTER REPAIRING VACUUM LEAKS, INSTALLING NEW COILS AND SPARK PLUGS AND REPLACING UNIVERSAL JOINTS ON FRONT DRIVESHART - VEHICLE RUNS NORMAL AND VIBRATION IS GONE AT 40MPH AT THIS TIME. *** MISFIRE IS GONE AT THIS TIME, BUT WILL RETURN DUE TO OIL LEAKING AT VALVE COVER GASKETS AND TUBE SEALS - LEAK REPAIR WAS DECLINED BY CUSTOMER ***

Sorry for the long post. Do those comments make sense? r2millers, how do I verify that which gasket I need to replace?

Thanks!

 

Makes good sense. To pdq' point, change out the o rings that seal the plug tubes and also the head gasket once you remove it for access. Replace the valve cover gasket too.

I was earlier referring to replacing the intake manifold gasket if indeed it's antifreeze.

Start with the above and check for fluid in that plug hole once driven a bit first. Replacing the intake gasket isn't a simple issue and I'd wait to verify first.

 

Are plug tubes those come with valve cover gasket? little grommets?
I asked them to keep the old coils..some of them were wet. Wiping it with kitchen towel shows a light brown color and smells oily. Under light I see green fluid too(?) perhaps I'm imagining. Is there a definite way to tell what it is?

Thanks!