My '91 740t has been going through some rough times. it just stalls on me. No hesitation or rough idle or anything. It just turns off whenever it feels like it. Sometimes it will go a week without stalling or on days like yesterday it will stall once on the way to work and twice on the way back. It's only a five mile drive. Sometimes there's a rough idle when it first starts but that always goes away within a few seconds. I replaced the air mass meter about a month ago, but i replaced it with a used one. I guess that could maybe be the problem but i don't know. The car's been running alot smoother since I replaced it. the check engine light was on before i replaced the air mass meter and remained on for about 2 weeks after i replaced it. It's off now and has been for a few weeks. I'm poor and clueless. can someone help me. It's been months since she's run right. Thanks!