o2 sensor bad?

I have a '96 Plymouth Voyager SE with the 3.0L engine. It is just about to
roll to 80K miles.

Symptom--> Start engine again after it has been sitting for a short time
(engine still hot) and it will 'usually' have quite a hesitation when you
first press on the gas. After it starts going in a few seconds, I will have
no further hesitations on that trip.

History--> Over the last 6K or so, I had a check engine light come on and it
indicated my front O2 sensor was slow. No other symptoms so I reset the
code and that one has not come back. About 5K ago I got a catalyst efficacy
degraded. I decided to take it to the dealer. They replaced the converter
under the 80K warranty - they made no comments about the o2 sensors.

My guess --> I have one or both O2 sensors that need to be replaced.

Questions -->

1. Does my diagnosis sound right?

2. Do I need to replace both or just the front sensor?

3. Is there an online site that has a good price on the sensors?

Thanks for the help!

 

Pony up for the Chrysler O2 sensor. Stay away from Bosch O2 sensors,
which Chryslers eat for lunch.

--

 

My dealer has a handheld computer gadget that he plugged into the Caravan's
diagnostic socket, and in 5 seconds he had a reading: upstream oxygen sensor is
bad.
Try it.

Morton

 

Ok - last night I went out and borrowed a scanner (obd-2.com scanner) . I
put it on and read the O2 sensor voltage output. Something seems strange....

Sensor 1 look like I was told to expect - kind of a sine wave - going up and
down from about .08 volts to a max of .98 volts -- that seems normal to me.

Sensor 2 - It started off with a sine wave, but the wave got smaller until
it was a flat line. It would stay around .8 volts while it was idleing
(around 760RPM). When I take it up to 1600 RPM it would drop and stay around
..1 volts, then back to around .8 when I let off the gas.


I dont pretend to have a great knowledge of how these should work. But I
just dont have the money to go out and start replacing sensors if that is
not going to help me.

Does anyone have some advice based on what I am seeing?

Thanks in advace for the help!