Lumpy idle and stutter under full load

[Pulse]

I'm getting slightly lumpy idle and a stutter when I put my foot down. The former is very minor and the latter is not always. A few times in 3rd, I've put my foot down around 2-2.5k revs and it will stutter.

Any ideas? I did run the fuel low for the first time ever at my last fill up (20 miles left on the range). Could it be that?

[Pulse]

Sorry, it's my Z4 3.0si.

[Pulse]

Nope it's never been run dry. The head was replaced about 1000 miles ago, maybe less. Could it be a leak causing the wrong air/fuel mix? It's under warranty but as there's no lights showing, they'll charge me no doubt.

I have been running it on 95ron for about 3000 miles now, so it probably isn't that, but maybe worth changing back to 97 or 99?

[ZeroSum]

Sounds like a vacuum leak.