ok so i scanned my car for codes and this is what i got. these coded keep comming back after like a week or so. The weard this is they jsut came back again a few days ago but the check engine light only comes on when its really cold out like -2 and colder. It was pretty warm out yesterday and the codes dissapeard but i know they will be back very soon so i want to get this fixed.

Oh an i did a seafoam treatment like 5 days before the car was scanned. As of today the engine light is still off, but once it gets cold i have a really good feeling the light will come back on

Chassis Type: 8D - Audi A4 B5
Scan: 01 02 03 08 15 16 17 25 35 37 45 55 56 57 67 75 76 77

-------------------------------------------------------------------------------
Address 01: Engine Labels: 4B0-906-018.LBL
Part No: 4B0 906 018 CH
Component: 1.8L R4/5VT G 0002
Coding: 16201
Shop #: WSC 78643

4 Faults Found:
16826 - EVAP Emission Control Sys: Small Leak
P0442 - 35-10 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16685 - Cylinder 1: Misfire Detected
P0301 - 35-10 - - - Intermittent
16384 - Unknown Error Code
- 35-10 - - - Intermittent
Readiness: 0000 0000

 

what year and engine?

 

For the first code:
16826/P0442/001090 - EVAP Emission Control Sys: Small Leak Possible Symptoms [ul][*] Malfunction Indicator Light (MIL) active [/ul] Possible Causes [ul][*] Evaporative Emission (EVAP) System leaking [/ul] Possible Solutions [ul][*] Check Evaporative Emission (EVAP) System Sealing [ul][*] Check Fuel Cap[/ul] [/ul]

 

For second code:
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected Possible Causes [ul][*] 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 [/ul] Possible Solutions [ul][*] 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) [/ul] Special Notes [ul][*] This DTC indicates that one or multiple cylinders are misfiring, but the ECU fails to identify the cylinder. [/ul]

 

For third code:
16685/P0301/000769 - Cylinder 1 Misfire Detected Possible Causes [ul][*] 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 [/ul] 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.

 

BTW, this is a very handy site for help with diagnosing after using VAG-com to check for codes.
It's very possible one thing is leading to another, and solving one or two things will return the car to normal.
Clear codes only AFTER doing some work to rectify the situation, see if they come back later.
http://wiki.ross-tech.com/index.php/Main_Page

 

thanks a lot for all the help, ya for the first one i aways have troubble filling up gass and the pump stops pumping every 5L beucase it thinks its full. Now i can go get it done, Again thanks for the help

what part do i need to fix this problem ? which is the first code

 

If you have VAG-com you could manually test the EVAP purge valve and other emission components. Basically you have to go into Basic Settings from group 034 to about 072 or so and test most of those components. This includes O2 sensors, CAT, EVAP purge valve, and a few other things. Some tests you gotta do with the motor revved up to 2k, others at idle. It's hard to really explain, but you can search for "setting readiness" and you should be able to find the article/how-to. If not, try over on the whoretex, i mean vwvortex.com.

You might just have a bad gas cap, or the purge valve itself may be faulty. I *think* it's the roundish thing on top of the airbox.

Edit: you might want to fuel up with a lower pump speed. Pumping gas too fast creates lots of vapors, which are recovered by the pump and sent back to the underground tank. Vapor is evaporated gas, for which you pay but don't get. Pump gas at the lowest pump setting, preferably in the morning.