My daughter says her van stalls when coming to a stop after driving for a while at highway speeds. She says the van starts fine, runs good and is fine while she drives on the highway. if she doesn't stop, all is good. The problem appears when she needs to stop, the engine dies. I drove the van around the city, no issues but she says the problem is more apparent when the engine is hot after hours of highway driving (lots of hills/mountains on our highways here in British Columbia).

Sooo, I was wondering if the brake booster has a vacuum leak, I have not tested it yet, but when I looked at the service manual, it says the van should have a filter in the vacuum line going to the brake booster. Her van is on the third owner, and it appears the filter is not installed. The van is a 1989 Dodge B250 and has a 318 with Holley Fuel Injection.

Does the filter matter? Any hints on how to test the brake booster for a vacuum leak? Is that uncommon?

Thanks in advance,

1989 Dodge B250 Camper Van 318 Cubic Inches or 5.2 Litres