Worried I've bought a dud

[golfyste]

16518       P0134             O2 Sensor Cir.,Bank 1-Sensor 1 No Activity Detected

(Sensor 1 is the sensor located before the catalytic convertor)

16556/P0172 - System Too Rich, Bank 1

Possible Symptoms
Irregular behaviour

Possible Causes
Fuel system
Excessive fuel pressure
Leaking or contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Air leaks after the MAF
Vacuum leaks
Improper seated engine oil dipstick
Stuck EGR valve
Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near HO2Ss.


16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected

Possible Causes
Air Intake System leaking
Fuel Supply faulty
Injector(s) faulty
Ignition Cable(s) and/or Spark Plug(s) faulty
Ignition Coil(s) faulty
Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
Camshaft Position Sensor (G40) faulty

Possible Solutions
Check Misfire Recognition
Check Air Intake System
Check Fuel Supply
Check Injector(s) and Injector Sealing
Check Ignition Cable(s) and Spark Plug(s)
Check Ignition Coil(s)
Check Exhaust Gas Recirculation (EGR) Valve (N18)
Check Camshaft Position Sensor (G40)

Special Notes
This DTC indicates that one or multiple cylinders are misfiring, but the ECU fails to identify the cylinder.


16688/P0304/000772 - Cylinder 4 Misfire Detected

Possible Causes
Ignition system
Fuel injectors
Fuel pressure
Running out of fuel
EVAP canister purge valve
Evaporative emission system
Low compression
Base engine problems
Controle Module damaged

Special Notes
This feature search for engine misfire in a specific cylinder. Most of the time the cause for a misfire is a lack of combustion in a cylinder due to absence of spark, poor fuel metering, or poor compression.

[golfyste]

so looks like you have a faulty o2 sensor and a misfire on cylinder 4 to start with.

so start by replacing the o2 sensor and check your spark plugs and ht leads to try and find the misfire then work from there 

[Nino]

Could that have anything to do with the coil packs?

But yes if this was my car I would personally do the following....

• Full service, including new HT leads/coil packs, New spark plugs.
• Take off the MAF and clean it.
• Take off the Throttle body and get it clean then apply new TB gasket.
• Fill the tank and use that Fuel treatment and take the car for a spirited drive to clean out the valves.
• Clear the codes and wait.

The "System bank running rich bank 1" I had that and I also had the O2 sensor crap after doing the above problem solved.