S4 b8 mis fire

[Roy Clarke 85]

hope someone can help,I keep getting a mis fire on bank 1,so I’ve replaced all the plugs and swapped the coil packs around and still getting mis fires on the same cylinders,

this is the fault code I’m getting so I replaced the intake manifold flat sensor which hasn’t worked,it mis fires on wide open throttle only,any help would be appreciated,thanks in advance

 

[PenttisHSR]

Check your coolant level, misfire on cyl 3 can be intercooler leak.

 

[Roy Clarke 85]

Check your coolant level, misfire on cyl 3 can be intercooler leak.

I forgot to mention that a year ago I replace the intercooler s and it doesn’t use coolant anymore,thanks for you time

 

[MuPPeT_ON_TouR]

Injector problem leading to the misfire? Can the injector get swapped over to a different cylinder to see if fault follows it?

Just a thought, though no real idea what I'm talking about.

 

[Roy Clarke 85]

That doesn’t sound like a bad plan mate,wouldn’t it not bring up a bad injector fault on the code reader tho

 

[MuPPeT_ON_TouR]

I don't know. Does it know if they are blocked or something. How clever is an injector?

Was just a suggestion, and it looks like you tried everything I would have thought it was first. In my mind I'm thinking they unplug and unscrew like a spark plug so should be easy to move.

 

[Roy Clarke 85]

I have had the injectors out before about a year ago,they under the supercharge and intake manifolds and just pull out mate,I may have a look on the weekend,thanks for your help

 

[MuPPeT_ON_TouR]

Found a few threads that have found injectors causing misfires but these were more for the older V8 S5 engines.

Found a nice page on common faults. (Clicky)
But nothing about injectors on it, still a useful page though.

If not coil pack, spark plugs or injectors then might be something crap like carbon build up on the valves, keeping them open.

Good luck.

 

[Roy Clarke 85]

Just to up date I found out why it was mis firing,it had blown one of the cats,so I replace both cats and it ran like a dream again until the mech broke on the gearbox,trade it in to audi and got an rs6 c7