Audi S3 Cylinder 4 Misfire Detected

[Flosmans]

Good evening all hope you keep well I need some serious help with this issue I'm dealing with,last week started up to go work drive off realised engine management light came on scanned with my own reader the following codes came up engine abit shakey exhaust popping not smooth on idle what so ever

after looking aroud on some forums get some info Ive done the following,Ordered 4 new ngk spark plugs & 4 new red r8 coil packs from awesome GTi ,all plugged in same codes were showing,did the swap around with spark plugs & coils to make sure it was none of these still codes were present next day.....

went to garage to see if they could spot the problem they change sparks & plugs done a compression test first was told my coil may be faulty tried the original ones no luck I left the garage saying mayb an electrical problem.

took it home seen that the under pipe connected to the pcv valve had a small crack in it went to pull the hose it crumbled in my hand,I order pcv valve kit,pipes gasket & valve fitted same code still present tommrow I will check the hpfp & the cam follower, took away my induction kit and spotted what looks like some oil leaking not sure what to look for next but some advice would be appreciated 38036380373803838039380403804138042

Sent from my SM-G998B using Tapatalk

[Crasher]

I had this exact same problem with the same codes on the same cylinder last week on a TTS which uses the same engine. I did plugs and coil packs plus a compression test which was near perfect with number 2 a fraction down (around 0.2 Bar) and it made no difference. Don’t worry about code P130A, that is the ECU reacting to the misfire on 2 by shutting down the injector... which makes the misfire even worse but saves the planet :aargh4: I discovered that the new PCV valve which had recently been fitted was causing crankcase pressure with fumes escaping around the cap so I fitted a new genuine PCV valve and this made the idle worse. I then disconnected the PCV hose from the inlet manifold and capped it, a new Bosch lambda sensor protection cap is a perfect no boost fit. This suddenly made the idle almost perfect and in measuring blocks the misfire on 2 was almost gone, just showing up every 10 seconds or so. With the oil filler cap off (you can do this with the inlet manifold port capped, I could hear some distinct rattling going off inside, when it came in, it had an almost identical air inlet system and there was a distinct thumping from the filter. I started to suspect carbon deposit build up around the back of the inlet valves and suggested removing the inlet manifold when I could also check the injectors but there was a cloud in my mind that it may be more serious and the customer decided to bale at this point.

[Flosmans]

what was your next step in finding the problem did you have an Idea what was causing this

Sent from my SM-G998B using Tapatalk

[Crasher]

I wanted to remove the inlet manifold and check for baked on breather oil deposits which stick to the back of the inlet valves and stops them seating correctly at idle speed but will not show up in a compression test. Then I could also remove the injectors and have them flow and pattern tested as this can cause a misfire. Unfortunately as I could not guarantee a cure and it may be money wasted due to an internal engine fault which would be totally unaffordable, the customer decided to get rid of the car.