[16v] Bad O2 sensor symptoms?

[doubt at inwave.com (Nate Mellom)]

Thanks Don, if I have some time this weekend I'll get under the hood and 
check stuff out.  I'm also suspecting vacuum leaks, so I'll look for 
those too.
Shoot me some pics with your 15s on her, eh?
Nate

Don Walter wrote:
> Nate,
> You should be able to disconnect the O2 sensor wires.  The car will then 
> run in an open (limp) mode.  If it runs better then its the O2 sensor.  
> I had to run mine this way for awhile till I got another O2 sensor.  
> Another test I seen my mechanic use is to put your finger on the live 
> lead and you other hand to a ground, the resistance in your body should 
> increase the RPM's  This will only tell that the rest of the system is 
> working.
>  
> Also double check all your grounds.  16V are very sensitive to having 
> good grounds.  There should be a small one from the firewall (usually 
> one of the bolts of the coil bracket).  The main one from the negative 
> of the battery to the frame (just behind the left motor mount) and then 
> to the Transmission has a tendency to go bad.
>  
> P.S.  I beat you to driving mine to work.  Got it licensed today.  Put 
> the Nokia snow tires on over the weekend.
>  
> On 11/17/05, *Nate Mellom* <doubt@inwave.com <mailto:doubt@inwave.com>> 
> wrote:
> 
>     All,
>     Got my '88 registered and insured this week, it's going on its first
>     trip (to work, at least) tomorrow!  It's super-ish cold (25* F), but it
>     started well after having sitting a week.  I took it to fill up the
>     tires, and to do a short test drive before I drive it tomorrow. It's
>     still got the stumbling/stalling/no power problem.  I didn't drive it
>     while it was cold, I started it late tonight, put on the plates,
>     transferred stuff from my '81, etc, so it was warm by the time I got to
>     the test drive.
>     A basic run-down of issues:
>     Upon starting, it held idle until it got warm, then the idle began
>     hunting, from 0 to 1500 or so RPM, occasionally dying.  It started
>     right
>     up though.  Left my driveway, and it stumbled and lurched a little until
>     I got the revs up, where some power kicked it, but it was still pulsy.
>     At stops I'd have to feather the throttle to keep it from revving too
>     low, and again, stumbles and pulses. Got to the gas station, left it
>     running, and it idled fine for 2 tires, then it began hunting again.
>     Drove it home, and still the issues.  Total trip lasted about 30
>     minutes.
>     The PO had done a bunch of work, including a new used distributor
>     (obviously included retiming the engine), fuel system pressure tests,
>     mizture adhustments, etc, all preformed by a reputable VW shop locally.
>     I'm suspecting the O2 sensor (tried to get it out, but it's very
>     stuck), and I have a used replacement I'm going to swap in, so we'll see
>     if that helps.  But I guess what I need to know, do these syptoms seem
>     like a failing/failed O2 sensor?
>     Thanks,
>     Nate
>     '81
>     '88
> 
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> 
> 
> -- 
> Don Walter - Waukesha, WI
> 1984 8V Audi 4000s (lastest addition)
> 1986 2.0L 16V TEC 2 Black Scirocco (see progress at 
> http://www.cardomain.com/memberpage/708939)
> 1986 2L 16V Toronado Red Scirocco (Ben's Car)
> 1988 1.8 16V Toronado Red Scirocco (sold on 3/29/04)
> 1984 1.8 8V Pewter Scirocco (sold years ago)
> 1971 Karman Ghia (sold)
> 1969 Karman Ghia (sold)
> 1969 Beetle (sold)