[s-cars] Running rough

[iain.atkinson at tesco.net]

Coil packs and the power output stage can give misfires under load, if it's misfiring then you will smell fuel in the exhaust as it's not burning properly. If it's not burning properly then you are also going to fill the cats with unburnt fuel too (that's bad).

Have you pulled the codes??? You might get G28 engine speed sensor and maybe the o2 sensor going out of range, had a similar probelm with my S6, the cure was the 034efi coil pack conversion, a new O2 sensor and plus just for good measure both the sensors down on the bell housing (g28).

I would bet on the coilpacks/pos first, my misfire i am sure was causing both of my codes as i earlier said.

iain
> 
> From: Adrian Hart <mail at red-wing.co.uk>
> Date: 2006/08/02 Wed AM 09:31:14 BST
> To: s-car-list at audifans.com
> Subject: [s-cars] Running rough
> 
> I've been experiencing a flat-spot at around 3000rpm ,and my MAP 
> reading at idle has dropped from 0.5bar to 0.3 or 0.4. Another problem 
> (I thought I had fixed by replacing the plugs and connectors but have 
> not) is that there is an intermittent and severe misfire. The car will 
> run sweetly, then suddenly lose a lot of power and run with throbby 
> "boomy" exhaust noise. This might continue for several miles then 
> suddenly everything will come back to normal and away we go. The 
> problem *might* be initiated when I hit a rough bit of road, possibly 
> indicating some sort of dodgy connection? What's the deal with the 
> coil-packs? Are they strictly go/no-go or are they capable of 
> functioning intermittently? ALso it tends to initiate when the engine 
> has been put under load at low RPM. Supporting facts are a petrol smell 
> in the engine bay when running like this and stinky exhaust.
> 
> Any help here greatly appreciated.
> 
> Adrian Hart.
> 
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