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73 Posts
Discussion Starter · #1 ·
Hi everyone, so today is Black Friday and I'm trying to get some deals on car parts. My check engine light has been on for a while and these are the codes that came up
P0313 Misfires detected with low fuel
P0300 Random/Multiple Cylinder Misfire Detected
P0128 Coolant Thermostat
P0301, P0302, P0304 - P0306 Cylinder 1,2,4,5,6 misfires
P0171 System Too Lean Bank 1
P0174 System Too Lean Bank 2
Any advice guys?

Premium Member
28,908 Posts
Buy the OBDFusion App and VeePeak interface from Amazon. Less than $30 for both.

Andriod requires Bluetooth, iProducts requires Wifi.

Replace the thermostat, repair the vacuum leaks and replace the fuel pump.

Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491




Cheap fluid transfer pump from your local auto parts store or Amazon.


A few rubber gloves, rubber bands and some cheap mini cigars from our local gas station or convenience store.

Also get a good, bright LED flashlight to locate the escaping smoke. Look deep in the engine compartment and under the engine if needed. Do not forget the dipstick guide tube and the lower CCV oil return line. These areas may be hard to see from above in the engine compartment.

After looking for intake air leaks, remove the oil fill cap and allow the crankcase to fully fill up with smoke, then replace the oil fill cap. Check for cracks in the valve covers and leaks around the grommets, half moons and around the perimeter of the valve cover.

Common areas of leaks:

Upper and lower intake boots
Upper intake boot around F connector
DISA main O-ring and shaft area
Vacuum hoses under the rear of the intake
Fuel pressure vent hose that connects to the F connector on the upper intake boot and under the drivers floor board where it connects to the fuel pressure regulator
CCV and hoses, especially the lower oil return line
Dipstick and dipstick guide tube
Oil fill cap
Valve cover gaskets and cracked valve covers
SAP vacuum line to Kombi valve on front of engine, this will not leak smoke because of the control valve under the rear of the intake
Power brake booster sucking jet pump and hoses.

Note that the brake booster usually cannot be smoke tested because of the input vacuum check valve at the booster connection.

Send me a Christmas present. :D

Premium Member
28,908 Posts
Lots of misfire threads lately.

Could it be the weather?
Yup, cooler weather brings on the misfiring, Lean problems and SES/CEL/MIL.

Often many of these cars are running close to the edge on Fuel Trim values, once the cold start enrichment becomes more important, any vacuum leaks can end up causing cold start misfiring.
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