sick a6

[Daz A6]

help needed please.
i have a a6 2.8 quattro (1998) with serious missfiring problem. it started a couple of days ago, sometimes it starts and runs fine but will occasionally missfire for a few seconds. sometimes it it starts and missfires from start up.
when missfiring it feels like its only firing on 3 cylinders, i thought it would be the coil pack but have tried a new one and its the same (intermittant) anynoe have any ideas?

thanks:zx11:

[Niall76]

How are the HT leads?

When was it last serviced?

[Daz A6]

hi niall76

ht leads all replaced last year, they look ok and are giving good spark at plug. last serviced 6 months ago, oil and filters etc,

[lonky]

look for a split vacumn hose, can cause the issues you describe, and cheap as chips to fix.