i have a decent vibration between 3000 and 3500 rpms with my 01 tiburon with auto trans. it feels like it is coming from the engine/ trans. you can feel the vibrations every time the engine is in that range, but it is the worst at highway speeds. The vibration completely disappears above 3500. I tried accelerating well above the speed that i feel the vibration and went into neutral and it is extremely smooth. so that eliminates the wheels, suspension and half shafts. the engine does not look like it is moving much when changing gears(motor mounts look good). no CEL or codes come up with a computer. i keep up with all the maintenance and the car has 92,000 miles. Any ideas i would appreciate it.
Thanks

 

hm.... exhaust/manifold leak somewhere?

when's the last time you changed your spark plugs or wires?

any Check Engine Light?

 

i change the plugs and wires less than 8 months ago and no CEL. i don’t see anything wrong with manifold, but is there any way to test them for cracks or leaks.

 

You can check for cracks by inspecting with a mirror

Accelerating above the speed which you were having the problem does not eliminate the wheels. However getting up to that speed and then moving the transmission into neutral eliminates the engine.

If the wheel is unbalanced it will get worse with speed. If your wheel is balanced, but warped or mounted wrong, you could simply be hitting the car's resonant frequency. The car can only react so fast and you may not notice it at slower speeds. The concept is similar to how you can take a speed bump very slow and you feel it, but then you hit the same speed bump faster, the shocks take most of the blow. Then if you hit the speed bump at 70mph, you catch air.

When I had a warped stock rim, it would vibrate at between 35-45mph, and I would not feel any vibration at any other time.

 

I had something that was similar to what you described not too long ago. Turned out I needed new wheel bearings. If you've never had them changed look into them because wheel bearings go bad on Hyundai's quite frequently.

 

I've heard that wheel bearing thing before, but I'm at 90,000 miles on the origonal wheel bearings. Never had a problem with them. I keep my wheels balanced and never hit a curb.

 

I disagree. Putting the car into neutral changes the RPMs, which have already been identified as a direct correlation to the problem.

I do agree that the wheels could be related. Several people have had problems with wheel bearings, but it seems hit or mimss. You're either pounded with problems over and over, or never have them. In the last 130,000 miles I've never had wheel bearing problems.

My advice - attempt to find anything that changes the problems, whether it makes it worse or better. Tapping the brakes, slowly pressing the brakes, etc.

 

^^ The engine was not yet identified as the problem. From what he's said, He's identified speed as correlation to the problem. Now we've got to isolate engine from the rest of the car.

 

i have the vibration every time i hit 3000rpm not just hat highway speeds, but it is the worst on the highway. i had the wheels balanced a month ago. when i put the car into neutral at 90 mph i let the car coast down to about 30 with no vibrations. i think i would feel the unbalanced tires or bad bearings in neutral..

Edit: Turns out it is the left transmission mount!
Thanks for your help everyone
lmao.gif