Any advice 2018 GTI , using more fuel than normal.

[lush4]

Hey guys as the title states, I have 140k km on a manual unmodified 2018 GTI, until now every tank of fuel has gotten 620-650km per tank since new.
The Last 3 tanks have been 500km. Seemed to happen over night.

No codes on OBDeleven. Brakes are not sticking. I just did spark plugs and airfilter to see if that helped. Plugs wernt black so i figure not injectors, Tire pressures are fine.

Any advice as to where i should start looking?

Cheers, .

[Sharkie]

I'd suggest cleaning the inlet manifold and ports from carbon buildup.

[petemac110]

I'd suggest cleaning the inlet manifold and ports from carbon buildup.

I see where you're coming from, but it would seem rather odd that any carbon build-up would cause a sudden and significant change in fuel consumption in a relatively short space of time. The impacts of carbon build-up tend to be progressive over time, and not like flicking a switch.

Personally, I'd be looking at the components that are part of the fuelling system and related sensors. A stuck injector, dodgy O2 sensor etc.

[Sharkie]

I see where you're coming from, but it would seem rather odd that any carbon build-up would cause a sudden and significant change in fuel consumption in a relatively short space of time. The impacts of carbon build-up tend to be progressive over time, and not like flicking a switch.

Personally, I'd be looking at the components that are part of the fuelling system and related sensors. A stuck injector, dodgy O2 sensor etc.

I don't disagree with taking a good look at the fuel system and sensors as well, but at 140K km, it is already overdue that carbon will be a problem if it has't been cleaned yet.

Carbon buildup does happen gradually, yes, but for quite a while, the buildup isn't enough to make a difference, and then suddenly, 1 day it is ... essentially, it reaches a tipping point where airflow is restricted beyond the abilities of the car to deal with it.

The first step, though, should always be a full diagnostic scan, as injectors, O2 sensors, and FPR will normally throw some errors, which can help identify the cause.

[lush4]

Update this is what i got after scanning while driving, now to research what it could be

OBDeleven data log


01 Engine

System description: 2.0l R4 TFSI
Software number: 5G0906259C
Software version: 0002
Hardware number: 06K907425B
Hardware version: H13
ODX name: EV_ECM20TFS0205G0906259C
ODX version: 001005
Long coding: 091900322444050B3000

Trouble codes:
P050700 - Idle Control System RPM Higher than Expected
Intermittent
P006800 - MAP/MAF - Throttle Position Correlation
Intermittent
U112300 - Databus error value received
Intermittent
Date: 2024-08-17 17:05:56
Mileage: 140555 km
Priority: 6
Malfunction frequency counter: 2
Unlearning counter: 255
Engine speed: 903.00 1/min
Normed load value: 14.1 %
Vehicle speed: 0 km/h
Coolant temperature: 79 °C
Intake air temperature: 38 °C
Ambient air pressure: 990 mbar
Voltage terminal 30: 11.210 V
Dynamic environmental data: 20961F41690000416A0001416B0000
U112300 - Databus error value received
Intermittent
P008800 - Fuel Rail/System Pressure - Too High
Intermittent
U012100 - Lost Communication With Anti-Lock Brake System (ABS) Control Module
Intermittent