200 10V stumbles, poor mileage

[Huw Powell]

Konstantine Bogach wrote:
> Hi Huw,
> forgot to mention O2 sensor:  it is only one year old, maybe two.   
> But... who knows, you are right, that would be an explanation.  I 
> checked duty cycle and it sweeps around 50% - same as it was before the 
> car started to stumble.   Would it be a proof of good oxygen sensor?

I think so, yes.

> Can I disconnect oxygen sensor connector when measuring? 

No, not to test the OXS, anyway.  But disconnecting it might provide an 
interesting data point.

> Would using a 
> scope give more definite test?

Possibly, but I've never used a scope.

Let's go old school - how good is the ground from the computer to your 
engine?

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/