Cadillac: '95 Eldorado engine surge

This is an enquiry for my father-in-law who has owned the car since new.


1995 Cadillac ElDorado engine surge

Symptoms:

While driving, the auto will begin to accelerate without the gas pedal being
depressed. With

foot removed from the gas pedal the auto will continue to accelerate and go
faster and

faster until the brakes are applied. After the acceleration/breaking cycle
has occurred once

or twice the automobile will then function normally for the remainder of the
trip.

A local mechanic has attempted to solve the problem by clamping off an
air-line which has

solved the problem somewhat but now the engine idles at a (slightly) higher
RPM than

normal/previously.

Any ideas?

Thanks in advance.


--
From 30 feet away she looked like a lot of class. From 10 feet away she
looked like something made up to be seen from 30 feet away. Philip Marlowe