That sounds like the same problem I am having with my 87 GL wagon the motor was swapped for another EA82 and the guy broke up with his GF and he lost interest. I got it running but soon as it warms up or you put it in gear she stumbles and after a couple of re starts then it stops and wont restart until its cold again. I thought maybe a head gasket but no coolant is lost. But one thing I noticed is if I can get lucky enough for it to stay running oil smoke starts to burn from the tail pipe. I am gonna mess with the vacuum lines some more and see if I can get that running problem sorted out first.