E300D rhythmic rough idle

[cewyattjr]

I think the long and short of it is that I'll have to take it back to the mechanic to look at hoses/o-rings again, but here's the symptom:

About every 30-45 seconds or so, I get a brief rough patch, the RPM drops at that time, and then back up to normal for another 30-45 secs. It does it whether the engine is cold or hot. Now peeking at the return line while idling I do occasionally see a group of air bubbles fly through -- so I assume that's the problem I've got.

At speed on the road, I don't feel any sign of roughness.

No sign of fuel leaking anywhere. I just had this puppy in the shop to deal with this o-ring thing...when it fact it was leaking fuel. At least that's solved.

-Chuck

[KarTek]

You're on to it... Leaky o ring upstream from the bubbles.