Hello and thanks for reading. I recently scored a very clean/nice 2000 t4r . I can see that the previous owner did a lot of work to mod and upgrade including 2"lift / new shocks / coils , 17" aftermarket aftermarket wheels (ultra motor sports Mako) , new radiator, and new rear driveshaft and U joints. When I got the vehicle I initially had some pronounced vibration at 60 mph and up. I had the wheels road force balanced ,an alignment and new lower ball joints. After some back and forth w the tire place we also worked out that the wheels must be carefully mounted and the lugs tightened in star pattern while on the lift to avoid off center mounting on the hub. huge improvement after this work. However some vibration always develops on the highway after ~30 min of driving 60 + mph. I'm not a mechanic, but starting to wonder if something in the drive line is heating up or if spark plugs heating up and maybe some misfire / skip causing the lingering vibration issue. Something getting hot over the passage of time and fluid or gear grease failing or breaking down. Maybe a transmission cooler is in order (if it you think it might help?) There is some loss of power also after the 30 min of driving. I'm looking for advice on this issue and very much appreciate your help.

Going to be hard for figure out this issue over the forum. Try to drive it and when it happens take it to the shop and have the mechanics look at it. At least this way the professionals will be able to figure it out in person.

Remove the front drive shaft or grease it and see what happens.


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Rear axle seals leaking and brake pads swollen?

Tire(s) bad and get a bulge after heated?

Front caliper dragging?

My only guesses right now.

Appreciate all the replies good people! I hadn't considered the possibility the tire could develop a bulge from heating up. Problem does come & go in addition to developing after the 30 minutes or so of driving, so that might be the most likely candidate. I'll let you all know how it goes and thanks again for your help!

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If all else is good check your'sway bar, steering rack and uca, lça, bushings.