missfire!

[missmouse]

I have an occasional misfire on my car (B5RS4) at about 3500rpm light throttle.
Ive changed spark plugs & dump valves, no obvious loose cables etc.
Is there any way that I could use my Vagcom to determine what is causing this?
If so, what EXACTLY do I have to do?:confused:

:1zhelp:thanks,

simon

[bearthebruce]

No fault codes? I am presuming that since you have VAG-COM, you did a scan for faults. What did you find?

Misfires can often be diagnosed by looking at the live measuring blocks. Knowing the where fuel trims are would be a big help. Since I don't know the engine, I can't be certain of which blocks to send you to but I would be looking at the info in groups 030 - 036 for the mixture information.

[missmouse]

Hi again Bruce,

Yes I did scan for fault codes & it says B1 lambda probe intermittent fault.
Do you reckon this could be the problem?

What should I do to check this-- have vagcom plugged in while I drive & see if the fault codes return ( I cleared them) when the misfire occurs?
I dont want to go buying bits like lambda sensors if its not that!

[bearthebruce]

I would like to see the actual fault code information before making recommendations. There is typically more information presented than just the fault code. Often the problem is with connections to these sensors. Sometimes the sensor itself is at fault. But, before I make any statements about that, I would like information. Could you post the fault code scan please?

[missmouse]

sure, thanks for that, Ill post them tomorrow maybe--- off out tonight!
Have as good new year!

simon