They were tried from 1982 to late 1991, and they proved unreliable.

That test proved too unreliable and never came into common usage.

During the race the Porsche 917 proved unreliable, and none was to finish.

Yes, they never got the price down and the optical disks proved unreliable.

But neither does one trust an animal that has proved unreliable.

He shut his eyes, tried to concentrate on sounds, but that proved unreliable.

The 2320 cc engine proved unreliable and few were sold.

The Di 6 however proved too unreliable, and was returned to the manufacturer.

And, having been purposely made vulnerable, they might prove unreliable.

The results of such studies have been proven unreliable.