1990 Buick Regal Custom for parts

This Buick ran great until a month ago. After putting in a new battery and then having a mechanic (a good hearted person) replace several parts it won't stay running (it will start then dies). Parts included intake gasket, park plugs, uel filter, ransmission pan gasket, acuum hose, rank sensor and coil pack with computer, ossibly additional parts but can't recall them so I'm selling the car "as is". The buck had to stop there..The underneath is quite rusted in spite of it being (heated)garage kept for years and the speedometer doesn't work. The heat/air conditioning works and the car is only average on gas.The tires are in good shape and the rims are rare for that model. I kept up with maintenance on it and it's inspected until August 2016. If anyone has this model car and needs parts?? Refer to pictures..Thanks for looking!!