[jyl]

My father is having a problem with his 1990 Jeep Cherokee (2-door, 6-cyl, stick, about 100K miles).

Every now and then, when driving around 55-65 mph on the freeway, the vehcle will suddenly and without warning begin to violently shake.

I mean really violently, it feels like the wheels are jumping off the road, the gear shift lever is bucking, your vision is blurry.

The only solution is to slow to about 15 mph, when the shaking suddenly stops. Putting it in neutral, lifting off the gas, applying brake, none of that makes any difference. Then you accelerate back to cruising speed and everything is fine again.

It doesn't happen often - I drove 200 miles today from the Bay Area to Laguna Seca and back, and experienced this shaking only once. The front tires have been balanced, the vehicle drives extremely smoothly. When it happened today, I was on a smooth stretch of freeway, might have been recently resurfaced actually,with no particular bumps that I recall.

Any ideas? One mechanic said the front end was worn out, $1,000 please. Another said the front end was okay. My father doesn't want to blindly throw $1,000 at the vehicle, without some good idea what is causing the problem. This is a "spare" vehicle.