I've a couple of questions: Where is this rumble coming from? Is this rumble accompanied by vibrations, or is it just purely a sound?
I ask, because I've also had rumbles at highway speeds. It was accompanied by a severe vibration; sort of like someone hammering the front wheels, or indeed, like a bearing problem as you've described.
Mine started anywhere between 90 km/h to 100 km/h (56 mph to 62 mph), and would occur anytime I'm in that speed range. It's more pronounced when the tires were cold, but when they warmed up the rumbling and vibrations lessened a little.
The rumbling and vibrations would mostly subside below or above that speed range.
Whenever it happened, it felt like acceleration was hampered a bit; much like what you're describing.
The culprit was both front lower control arm ball joints; they were shot.
Since replacing those, the rumbling and the vibrations stopped.
Another question: Do you hear clunking sounds when you turn or go over bumps? If yes, it could well be the ball joints. To my understanding, you check the conditions of the ball joints by jacking up the car, putting it on jackstands, and then shaking the wheel back and forth, side to side.
If it is indeed the lower ball joints, do be sure to replace both at the same time, even if one of them is in good condition.
Hopefully this helps, and that the problem gets solved soon!
Last edited by Underthebluesky; 07-23-20 at 04:08 AM.