S3 with a misfire

[Matto]

I was asked by a friend if I could scan his 58 plate S3 as it keeps throwing the EML up. It has been into Audi a couple of times and on one occasion the report says they found a misfire on cylinder 4 and running lean. They changed a crankcase breather valve or something at the same time.

It is still doing the smae and the problem is still there. The car has a leaking servo which I'm not sure could relate to this issue.

So here are the codes I'm getting:

Address 01: Engine (CDL)       Labels: 06F-907-115-CDL.clb
   Part No SW: 8P0 907 115 AB    HW: 8P0 907 115 B
   Component: 2.0l R4/4V TFSI     0010 
   Revision: 5BH16---    Serial number: AUX7Z0HNFNH0E8
   Coding: 0103000C180F0060
   Shop #: WSC 06314 000 00000
   VCID: 72E1FA276DD4A68E9D9-8027

2 Faults Found:
000768 - Random/Multiple Cylinder Misfire Detected
               P0300 - 001 -  - Intermittent - MIL ON
             Freeze Frame:
                    Fault Status: 10100001
                    Fault Priority: 2
                    Fault Frequency: 18
                    Reset counter: 255
                    Mileage: 76010 km
                    Time Indication: 0
                    Date: 2014.06.30
                    Time: 10:47:45

             Freeze Frame:
                    RPM: 2235 /min
                    Load: 16.1 %
                    Speed: 30.0 km/h
                    Temperature: 50.0°C
                    Temperature: 18.0°C
                    Absolute Pres.: 1010.0 mbar
                    Voltage: 14.605 V

000772 - Cylinder 4
               P0304 - 001 - Misfire Detected - Intermittent - MIL ON
             Freeze Frame:
                    Fault Status: 10100001
                    Fault Priority: 2
                    Fault Frequency: 18
                    Reset counter: 255
                    Mileage: 76010 km
                    Time Indication: 0
                    Date: 2014.06.30
                    Time: 10:47:45

             Freeze Frame:
                    RPM: 2235 /min
                    Load: 16.1 %
                    Speed: 30.0 km/h
                    Temperature: 50.0°C
                    Temperature: 18.0°C
                    Absolute Pres.: 1010.0 mbar
                    Voltage: 14.605 V

Readiness: 0000 0000

After a bit of Googling I found a couple of websites with some saying plugs or coil packs could be possible issues. I started by swapping coil packs 3 and 4 over so see if the misfire transferred. It stayed on cylinder 4 so told him to get some new plugs. Fitted those yesterday but it is still the same.

My knowledge on these engines is quite limited so I'm just wondering if anyone else may have some ideas of anything simple it could be. He is thinking of getting rid as he reckons red cars he owns are always cursed haha.

@vRSAlex Here is a photo of the plugs that came out. I was expecting number 4 to look different to the other but it didn't. Any ideas? Appreciate your help over the phone too the other day 

[Scottymon]

What's the cam follower like?

[Matto]

What's the cam follower like?

Couldn't tell you. Like I say, I'm not familiar with anything with spark plugs 

[GrayMK5GTI]

Most probably an injector failing 

Getting more common on K04 engines cars

[Saintsteve]

Most probably an injector failing 

Getting more common on K04 engines cars

Injector all day long

[Matto]

That's abit of a bummer. Is there anyway of checking for a bad injector with VCDS? I had a good look through the measuring blocks but nothing stood out. Or electrically with a meter?

[GrayMK5GTI]

Think it will have to come out to test it properly, although I'm sure there is some sort of function test available with VCDS

He's best not driving it hard, or he could melt a piston 

[Saintsteve]

That's abit of a bummer. Is there anyway of checking for a bad injector with VCDS? I had a good look through the measuring blocks but nothing stood out. Or electrically with a meter?

If you've ruled out everything else and it basically will leave the injector as the issue. While the inlet manifold is off, it's well worth cleaning the inlet valves as they will be clogged up aswell .

[rich83]

How much are injectors?

[xjay1337]

Used S3 injectors go for about £160 don't they for a set of 4....

[pudding]

Don't use s/hand injectors.

PSI sell a set of 4 for under £500.   I doubt you'll get cheaper than that unless you have special sources.

There won't be any piston melting going on, don't listen to such nonsense.  It's only at idle.  The nozzle has gone a bit lazy but is fine with higher rail pressure.  Might be able to free it off with a Terraclean but personally, stick a new set in.   It's just the nature of the beast.   Walnut shell blast the intake ports whilst you're there.  Special tool required for injector removal, which Laser Tools sell.

[GrayMK5GTI]

Don't use s/hand injectors.

PSI sell a set of 4 for under £500.   I doubt you'll get cheaper than that unless you have special sources.

There won't be any piston melting going on, don't listen to such nonsense.  It's only at idle.  The nozzle has gone a bit lazy but is fine with higher rail pressure.  Might be able to free it off with a Terraclean but personally, stick a new set in.   It's just the nature of the beast.   Walnut shell blast the intake ports whilst you're there.  Special tool required for injector removal, which Laser Tools sell.

Is it only at idle?? 

Driving a car hard with a dicky injector isn't exactly going to end well is it

[Matto]

I haven't driven the car myself but it is very noticeable at idle and as soon as the misfire count is enabled it shoots straight up.

[Cupra_Jay]

Injector failing happened to me unfortunately I didnt know about it till it melted my piston. Get those injectors checked immediately. Your bill might be in the 100s of pounds but it will save you spending the 1000s that I did to get mine back on the road