I've read some of the posts concerning loss of power while driving along at a normal speed. My 1991 240 has done this to me while driving down a semi-steep incline. After I applied the brakes and tried to move forward, it sputtered and it almost felt as though I was having a front tire issue but it was an abrupt loss of power and although it nearly stalled out, I was able to recover and move ahead without any more problems (it almost felt like a throttle linkage problem).
In April, following this first episode, it began idling roughly and I took it in for service. The PCV valve was replaced along with spark plugs and wires. Then it happened again within the past month. This is very scary while on a busy road and I'm nervous about driving too far. Today my sister drove it and the same thing happened to her twice within minutes. So, if anyone out there has any more ideas to share, I'd like to hear them. Guess I'll be trekking back to the garage again although I'm trying to avoid this move. Thanks.