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rough running

Suzi ( UrS4)'s name ....has this optional extra  

normal service is fine, niiiice smoooooth ride.... THEN it feels like a switch is made in the engineroom dept, then it feels lumpy as your grany's custard  

feels like I loose a cylinder but when i give it a light dabble on the go faster pedal, it smooths itself out again  

Grizz mentioned the harmonic damper is tired so have a good replacement lined up being fitted in Sept along with the gearbox change.

The other day sat at the lights I put the car into Neutral (autobox) and the engine was rocking ( circa 800rpm)!! definately felt like it wasnt firing on all 5 pots or maybe it was but missfiring badly.

I had the idle position sensor changed recently because the 1 already there had a few codes on vagcom pointing to it ( still got the old one)

my vagcom doesnt like Suzi so wont work because its not a few hundred quid genuine lead  

any suggestions what else it could be please?

what would the symptoms be on a dying coil pack ? ( I have changed 1 or 2 the previous times I have owned the car)
would the harmonic damper feel like its lost a cylinder when its worn out?

could it be the MAF?
normally Suzi is quiet quick for an ole girl but when this sensor/ switch thing does its thing, She is slow to pick up, feels lumpy and cant be arsed or is that me    

99% of the time the car is as it should be and pulls really well,smooth pickup and life is as it should be... other times when She's rockin' acceleration is lethargic to say the least... feels lumpy and aint fun to drive BUT THIS IS intermittant so whatever it is I dont think its mechanical otherwise it would be like that all the time  !!
in fact the sensation is like driving a manual car too slow for the gear your in, jerky progress but when i give it more revs its smooths itself out but acceleration isnt as hard as it should be regardless of the speed

suggestions please gents  

If it was a B6 I'd say it was a coil pack. Does Suzi have CP's or plugs? Maybe a plug is dead/dying?

AliGod78 wrote:
If it was a B6 I'd say it was a coil pack. Does Suzi have CP's or plugs? Maybe a plug is dead/dying?

It does have Coil Packs.

Does sound like a Coil Pack issue, however, there is also the POS Switches (amplifies the the power/signal to the Coil Pack from the ECU) that sits on the Bulkhead (2 of them) that can cause the Coilpack to malfunction if goosed.

Good thing is that there is 6 ports (3 in each of them) so if one is knackered, you can have the wiring fed to the spare POS Port.

hi Ali

the 5 pot has coilpacks, I think Grizz changed the plugs last Sept, I'd have to check the invoice.

symptoms isnt always there so suggests its something in the wiggly dept thats not feeling very well.  


thanks Matey !!  definately sounds thats the symptoms there, I have spoken to John at Bedrock Motors in Motherwell so gonna pop over there when he can fit me in.

I'll send him that link as well.                    


spoken to the guy who is gonna change my box for me, he has loads of spare coilpacks, POS things as well and knows how to rectify whats up with it.
not getting done until Sept so gives me a bit of time to save up  

Nice one! Good luck in Sept!  After that you can sell her and mod the RS      

No chance !!!

Only 5 UK registered auto S4 saloons left on the road so this one is staying with me....

Besides in her current state of tune or out of tune is probably more accurate I still managed to keep Noodles in check    

last weekend was a busy one !!  Friday I travelled to Leeds to catch up with the Mrs then head to Liversedge for a friends wedding from Classic Audi forum.... Saturday my brother in law and I headed to Scarborough ( me in my UrS4 and Karl in his UrS6 avant   then on Sunday it was steam bits in the Aygo back up to Stirling for another wedding  

en route on an uphill section of dual carrageway following Karl my car decided to cut out      so I drove onto the grass verge by the side of the road, turned it off, then tried again... fired up first time!! Karl stopped on the crest of the hill in a layby so I pulled in behind him and told him what happened !!!  

When we arrived at Scarborough ( with no more bum clenching incidents) I told Spink what had happened and took him for a quick drive to see if the symptoms re appeared, cut to the chase, Spink has used the car daily and it happened to him again so he thinks i have a dodgy fuel pump relay so he is gonna stick a known good one in and see if that helps and also see whats going on with vagcom...

There was another silver auto saloon UrS4 with Spink so it was a good idea to get a photo of 2 of the remaining auto saloons in the UK:

THEN JUST before we left to head back to Leeds... another UrS4 saloon ( manual) turns up

then another pal sends me a link to yet ANOTHER silver UrS4 auto saloon for sale

so out of the remaining 5... 3 are the same as mine          

my rear suspension is riding waay to high so thats getting sorted, harmonic damper is getting changed, car serviced and gearbox replaced with 1 thats done 125k LESS than mine  with fresh gearbox oil and strainer fitted.
failed its mot on a dead rear foglight, bolt missing from the exhaust and emissions so could be tired cats? new lambda sensor was fitted by Grizz last Sept.Spink says he can easily sort out the emissions so no worries there I suggested ditching the cats  

hope get the car back in a few weeks.    

Spink has my digi  camera so will be taking loads of phots for me as work progresses.

Check your plugs! I just had a severe rough running problem due to loose plugs on my RS4 & I had one blow out completely on my S2 & my brother used to have a UrS4 & it happened to him too!
Anyone used Loctite on these? ( Ive not tried tightening them more than  30NM - maybe that would do?)

Cheers for the heads up  

The majority of the time it runs as smooth as when it was new BUT occasionally it has a wibble moment!

Fingers pointing at the relay for now, I have been told that the spark plugs for these cars are now obsolete but the tooling equipment was taken to the far east and now being churned out there but not as good quality???

Another plug was mentioned so I'll get mine looked at as well.


really? the plugs I fitted recently ( RS2) were stamped "Germany" on the metal bit. I think I may try NGK plugs next time ( which are made in far East! LOL)

I'll find out the plug number. Forum Index -> Audi urS4/S6 quattro
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