low rpm shudder/vibration

[cplchris]

i have a 2006 kj 3.7 4wd, lifted about 3.5 or 4 inches from stock, 245 75 16 all terrains. it has 100,8xx miles on it. today i noticed a weird shudder/vibration at lower speeds.

the vibration starts around 15-20 mph and seems to go away when i accelerate.

if i get up to around 40 or higher and let it coast down the vibration/rumbling/shudder starts around 25 mph and when i start braking seems to increase.

once im around 10 mph and slowing to a stop the vibration feels like a shudder until i stop.

the problem does not change at all with O/D off

i also went to a parking lot and put it in neutral around 10mph and it still does the same thing.

temp guage is reading normal
no CEL or other warning lights
i have always kept the oil changed and use bg moa
****** and t-case were flushed and serviced around 10,000 miles ago
diff fluids were done about 5 or 6000 miles ago
spark plugs were done about 30,000 miles ago (ngk iridium ix)

so far the possibilities i have come across here and thought up in my own head are these:
spark plugs (i have new champion copper cores i'll be putting them in in the morning)
maybe an ignition coil on it's way out (will test tomorrow)
crankshaft position sensor
camshaft position sensor
O2 sensor
u-joints (they have been vibrating lately will probably change tomorrow)

anyone here have the same problem? if so what was your solution?

thanks for any help.

 

[Hedsic]

Mine does this but not all the time. Just randomly every so often.


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[Birdman330]

Run your hand clockwise on your front driver side tire, then run it counter clockwise in return ON THE TREAD not the shoulder not the sidewall THE TREAD. If feels super smooth counter clockwise with dips and waves, super rough clockwise there's your answer, the tires are all chopped up on the front. Chopped tires will cause vibrations, jutters and noises at low/high speeds.

 

[cplchris]

tires are fine but im going to balance them and rotate them tomorrow as well

 

[cplchris]

Well I got the problem fixed yesterday...it turned out to be u-joints on the rear drive shaft...the one at the rear diff was practically siezed in place.