My skoda octavia 1.6 fsi 07 has 72miles has been v good and drives well. Annually services with dealer and no previous problems

 

Recently, it has started to have an engine misfire while stationary and it does not appear while driving. There are no codes coming up and no engine management light which comes up. I took it to a garage and changed spark plugs and also ignitions coils but no difference. The misfire is when the engine heats up to operating temp and while stationary. Anyone able to advice what could be other reasons for this kind of misfire to look for?. Thanks 

I wonder if it could be running a bit lean? A VCDS scan might be a good start.

Although it wasn't probably VCDS, The mechanic today plugged a tool into cars OBDII port  and looked for various parameters but it didn't show any diagnose fault codes

Hmmmm, missfires should be reported as ecu fault codes. Like I say could just be running lean which is only noticeable as missing at idle due to lack of fueling. Maybe the start of a sensor failure somewhere that isn't bad enough to be picked up as an ecu fault yet (Maybe MAF or Lambda or some such?)

Has your mechanic at least checked for vacuum leaks?

It would be really helpful to have the car plugged into a scanner and checked while running under these conditions, using VCDS or generic OBD2 with live data. Fault codes are only an indication of a specific test failing, there are many problems that could occur just outside of the test threshold that could cause bad running.

The Coils replaced might have been an un-necessary expense but at least done now.

So are you sure the spark plugs fitted are the correct ones with the correct gap.

?

What about the air filter, is it checked, clean and dry or replaced, 

& the Fuel Filter, even if said to be 'Fitted for life', they need replacing, that is why they are available as a consumable.

I took it to an engine tuning centre. He also checked with the VCDS and stated that no faults picked up. But he did a throttle body reset and with ECU reset. He stated to come back after a week or so for re-scan.  The problem hasn't gone. I am not sure if this is relevant. I was previously using  0w30 c2/c3 VW50400 oil and replaced it with 5w30 vw50400 genuine oil. After this I noticed the misfire behaviour. It may be coincidental. 

The spark plugs are NGK and I have replaced the air filter, oil and fuel filter at the time of engine oil change....

@hifiboy - Well, unless wiring was disturbed during the oil change, I can see no reason why that would cause a misfire.

 

Also, and more generally, I'm more used to insulation breaking down when hot and under load than at idle.

 

So do you have the old plugs? If so, take one of them and replace each of the new ones in turn, in case you have a bad plug.

hifiboy,

NGK plugs but which ones and what gap should they be at, do you know?

 

So do you know has the fuel filter been changed, 

and have you tried maybe a tank of Super Unleaded 99 ron just to see if it has any affect on the mis-fire?

I have changed the fuel filter and again replaced all four spark plugs with VW genuine parts.

Also tried a week with the RON 99.

The misfire continues on idle and is more worse when engine hot.

 

Had a VCDS check again and the engine tuning centre engineer who a look had said that readings are fine, he cannot find a fault and stated that it CAN be normal for an FSI  engine to do this. The second mechanic mentioned to keep driving until it gets worse and it throws codes etc...

I am worried about the engine that if it continues like this it will get damaged. so far up until few weeks there have been no probs.

Please see attached the video about the misfire from exhaust.

VID-20171111-WA0000.mp4

 

So, just to recap. This only happens when idling? It is worse when warmed up to operating temperature? It brings up no codes and no pending codes?

If it only happens at idle, does it improve with more load from ancillaries (AC, blower, etc.)?

Also, confirming that you have replaced all filters, coil packs and plugs?

 

Has the engine ever stalled due to these misses? Has the engine been run while monitoring (with VCDS or a scan tool)?

Did you try disconnecting each plug in turn, to clarify if it is random or a single cylinder misfire?

 

I'm curious about how the fuel trims behave. These are called STFT and LTFT on generic OBD2 scan tools and something like lambda learned values in VCDS. Any chance of a report on these?

 

A misfire on its own shouldn't cause any damage to the engine itself, depending on the kind of miss, items in the exhaust stream could have their life reduced. It is possible, however, the causes of some misfires can lead to damage so it is prudent to get the problem dealt with as soon as you are able, which you are in the process of doing.

Edited 18 November, 20178 yr by LightRain

I have the same problem but mines a diesel, I have recently noticed that switching something on which draws power like the heated rear window the car ticks over normal, switch it off again and it ticks over like its misfiring again. No codes either showing up, Cannot figure it out...

Have you had a compression test done?

I had a similar fault years ago on a Peugeot engine. Slight misfire on idle, but hardly noticeable when driving. Eventually traced it to a cracked exhaust valve.

I will get the lambda learned values in VCDS. There has been no pending codes and has never had engine light on or codes on VCDS.  

Yes, this only happens while idling. The car has always started without problems and spontaneously with ignition. There has been no engine stalls due to misfire. It just continues and quite noticeable when engine hot. When the engine is cold I don’t feel the jerks and the misfire sounds from exhaust. It does not improve with load from ancillaries.

I have changed all the filters, coil packs and plugs with genuine parts.

I have not noticed loss of power, jerks while driving but I think there is reduction in MPG. Although, I am not sure if this is because of this misfire problem or cold weather. Previously I was getting around 44 mpg on the motorways and now around 34- 38 mpg.

That's good, even if they show no abnormality they can potentially tell something.

 

There's a lot of things that could cause idle misfires (every suggestion so far could be a valid suggestion under the right conditions), so it makes sense to look at things in order of difficulty. Depending on what your fuel trims are like, they could give a route to follow.

I had another scan done and being told that there was a fault for 'air temperature sensor' which is located in the engine cover near the air filter. Was told that it could be creating the lean poor idle . Clearing the fault has not resolved the problem so next week would be changing this sensor.  

I have continued to get the misfire fixed but no success. It continues to misfire at idle with no problems when driving.  So far had replacement of:

:Post cat lambda sensor

coolant sensor

air intake temp

Also had vacuum compression tests and found to have very good in all 4 cylinders.

New all spark plugs and one new coil in cylinder 1. This new coil was moved to all other three cylinders but no change in misfire. It is now in cylinder 1

I have had VCDS scan thanks to Briskskoda and below are some results. Shows misfire count in Cylinder 1. Also post fuel trims and full log is attached:

 

 

 

.   

 

 

Please advise, where do I go from here. I am interested in the cure.  

 

 

 

Log-OCTAVIA1-TMBBB21Z372147326-123010km-76434mi.txt

Duel mass flywheel? 

I would swap the injector from cylinder 1 into another cylinder, you have looked at most other things so this seems the next logical step.

Edited 26 January, 20188 yr by SuperbTWM

How is mass wheel related to misfire?. 

Hello

 

The engine line flickered for few seconds when I started the car.

 

VCDS scan picked up a misfire and showed the following after this:

 

 

000768 - Random/Multiple Cylinder Misfire Detected 
               P0300 - 008 -  - Intermittent
             Freeze Frame:
                    Fault Status: 00101000
                    Fault Priority: 0
                    Fault Frequency: 2
                    Reset counter: 255
                    Mileage: 124280 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 17:44:42

             Freeze Frame:
                    RPM: 840 /min
                    Load: 31.4 %
                    Speed: 1.0 km/h
                    Temperature: 20.0°C

000769 - Cylinder 1 
               P0301 - 008 - Misfire Detected - Intermittent
             Freeze Frame:
                    Fault Status: 00101000
                    Fault Priority: 0
                    Fault Frequency: 2
                    Reset counter: 255
                    Mileage: 124280 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 17:44:42

             Freeze Frame:
                    RPM: 840 /min
                    Load: 31.4 %
                    Speed: 1.0 km/h
                    Temperature: 20.0°C

 

 

Can please someone advice, what should I now be looking for to fix the misfire which comes up only at Idle?

 

Sell it

Hello, 

 

Can anyone please suggest an expert place/ engineer in Essex preferably or around London, kent  to me who can help me with problem. I am sure if I have the right expert to fix misfires the problem of the problem can be fixed. This will avoid me buying another car....