I have a MK7 GTI car is a 2014 (63 plate) with 70k on the clock.
I had the car mapped to a stage 1 and started having wastegate issues so reverted back to stock and had the wastegate sorted..
About 3-4 weeks and 1000 miles later the car developed a hot start issue and stalling. Hot starts would either crank for longer or start up drop to around 500rpms and either die or manage to catch back up and idle normally. Also when coming to a standstill at a traffic light or if start/stop kicked in it would struggle to start and idle roughly. No engine codes or anything..
I started looking into it and found a common cause to be the Cam adjuster magnets. Replaced with genuine VW replacements even though the old ones did seem to be failing no difference. The car ran a bit better for a few minutes and back again...
Then out one evening and had the loss of oil pressure stop immediately.. Luckily I was already parked and the car was only idling turned the car off immediately and got it to the garage.
No codes still they had a look at multiple things and could only recommend changing the fuel pressure regulator, spark plugs and oil. Had this done still no luck..
Had another garage look at it and they first had a soft code for the MAP they removed it cleaned it reinstalled no codes for this. Drove it a mile or so then soft codes for O2 Bank 1 Sensor 1 carried out a live data test and found it was working fine and the code cleared and never returned.
At this point had it looked at by a tuning company with VCDS however still no engine light and nothing seemed to be out of the ordinary on all the checks they done.
This morning started to have a look again and found now the issue is also present on cold start and seems to be getting worse. Started unplugging coil packs, MAP sensor & oxygen sensor finally managed to get the car to throw up some codes. Now everything is plugged in cleared the codes to see what returned and still seeing the following codes:
Multiple Cylinder misfire
Cylinder 1 Misfire detected
Cylinder 4 Misfire detected
O2 Sensor Negative current control circuit Bank 1 Sensor 1
I disconnected the O2 to see if this made a difference to the running of the engine however no difference..
Before i start throwing more parts at it blindly i just wanted to know if there's anything I've missed or anything else I should check.
