shudder at high speed w/ specific symptoms...cause?
 

02 hyundai sonata v6... the whole car shudders around 55-70 ( but not all the time?). Steering to either side makes it worse.

The other clincher is is that it only does it under engine load (RPMs don't matter). coasting, even in gear, at these speeds makes the problem go away.

I checked the rubber boots under the car, nothing ripped.


Other known issues:

Front tires are JUNK. unevenly worn on the insides, but then again, they keep going flat, (and I get sick if refilling)... corrosion on the wheels makes the seal bad. So I'm unsure if its just low pressure wearing them badly, or if its the alignment...or..tirods? or.....what.

warped front brakes, possibly a sticky caliper, though not sure.

Re: shudder at high speed w/ specific symptoms...cause?
 

It sounds like a bad axle, or axles to me.