Help Shuddering, Low power. Coil Pack? Spark Plug?

[TomCrox41]

Hi all,

Ok so been for a bit of a drive down to Dorset this weekend. about 20 miles before we arrive down there on friday the car started shuddering loads when accelerating at any speed. But there was no warning light appeared.

Drove it home today and still doing it but again no warning light. Also noticed a severe increase in fuel consumption!
(also used my torque app on my phone to read any warning codes and there was none)

I serviced it a couple weeks back and this is the first real drive since then.

After looking on here it could be the coil pack, however surely this would throw up a light??? Could it be a cracked spark plug? (had one before on my old vectra and had similar problems)

Gona have a good look tomorrow, Any one got any ideas if nothing looks out of the ordinary???

 

[<tuffty/>]

Would be useful to post model/year of car but I see from your profile you have an APY S3?

If thats the case then you will haev the bolt down coil packs... these are generally trouble free but I have seen the cheaper Beru coil pake up out of the box (these are the ones that you can buy from GSF or ECP)

If you have some of these then its plausible for a coil to go bad... as for a cracked plug... do you know what ones are in there? std fitment are NGK platinums but Bosch Super 4's are a bit iffy as are Denso plugs... have seen shattered ceramic on Denso's and would never use them....

Do you have access to VCDS? a scan for fault codes would be a good start... these intermittent faults don't always turn on the CEL

<tuffty/>

 

[TomCrox41]

sorry yer that would help,
its a 1999 S3 pre-face,

I did the service, its got bosch super 4's.

As for the coil packs i'm not sure what is in there, but my guess is that they are STD ones as before i got it all the work was carried out by audi.

I brought a VAGCOM system last week but its still at the stores at work where i had it sent to

 

[smurfworth]

knackerd flywheel?

 

[TomCrox41]

Does any one know how the ECU detects a cylinder misfire?? Incorrect resistance/current from coil pack or injector??? Or is it cylinder temperature? or instantaneous accelerations of crank?

 

[dre_S3]

What's up with the super 4's Tuffty just put them in mine ?

 

[TomCrox41]

Solved this conundrum!!!

It was the coil pack on cylinder one.

However i found it by disconnecting each coil pack in turn and see which one didnt make the engine run any worse. But while doing this i noticed the the CEL did not light up at all even when it was running to 2 cylinders!

 

[Vex182]

Sounds the same as when my coil pack went, had no real power, a lot of vibration as soon as it started to boost and it drank fuel! Had no warning lights too. I'm running the Bosch Super 4s too.

 

[<tuffty/>]

What's up with the super 4's Tuffty just put them in mine ?

Have had misfires with them... I only ever use NGK's... never had an issue with them...

<tuffty/>

 

[dre_S3]

Would you recommend changing them then only on a standard s3 don't want to folk out on an other set really I will see how it's like once I have the car back on the road I really hope fitting this catch tank and getting rid of all the hoses sorts out my problems with the car holding back ?