91 20v 200 Stalling at Hwy Speed

[bdealva]

My son's 91 20v 200 was just in the shop for: (1) replacement of the heater/air conditioner blower and (2) replacement of the fuel filter. Everything seemed fine when he drove from the dealer several city blocks to his place of residence (college dorm).

When he next used the car on a trip w/ highway driving, he discovered a serious performance issue; at highway speed (primarily over 40mph) the engine cuts out with a distinct knock when he steps on the gas. The problem does not manifest if he comes up to speed gradually but consistently appears with any significant throttle application.

It seems likely the appearance of this problem after the dealer service is more than coincidental. I suspect something (vacuum hose?, electrical connector?) is disconnected. I also suspect the problem may have something to do with the turbo control system.

My son will be returning the car to the dealer but it would be great to have any insight as to whether the issue could be related to something that occurred with the earlier service.

Thanks in advance for any help!