bmw 525i e34 spluttering problem

[cars1993]

Hi all. Had my e34 for about 3.5 months now and theres always been a very slight splutter on idle & acceleration, runs rich and uses lots of petrol.

The code thats come up is dtc 100 ignition output stage- ignition bank 1

this is the only ones that come up.

any ideas? its not as quick as it should be :/