Volvo 960 Popping Sound when accelerating

I’ve got a 95 Volvo 960. Yesterday my car started making this clunking, or popping sound as I accelerated (pop…pop…pop). It speeds up as I speed up. Suspecting it had something to do with the driveshaft, I accelerated, then put the car in neutral to coast. The sound went away. I tried throttling in neutral as well and no dice. The sound happens 100% of the time and only when accelerating. Any ideas on what it might be?