The O2 is ignored by the computer right after startup.

"RCM" > wrote in message ...
> One of the sensors going bad.. forget which O2 ?. '92 and 98 Accords did it after
> sitting unused for a month. About a 2000rpm swing even after warmup.
>
> User38221 wrote:
> > Sometimes when i startup my 1994 Civic EX (vtec) the engine revs back and forth
> > between 1500 and 2000 rpm a few times before finally settling down at 1500
> > (then dropping lower as the engine warms up).
> >
> > anyone know what might be causing this?
>