David,

You nailed it. It was a ground fault on the shielding on the O2 wire. It was a self inflicted problem. The new O2 sensor had a female connector, the wiring harness connection was also a female connector. So no problem, I stripped the insulation and crimped in a male spade connector.

What I didn't realize, until your post, that that wire had a ground shield around the center wire. So when I put the male connector, I grounded the circuit, and caused the crappy running.

Went out to the van, redid the connector, after stripping away a bit of the ground shield. Now it runs like a top!

Thanks David! And thanks to everyone else who suggested solutions.

Ric

Sent from my iPad

> On Jan 6, 2016, at 17:22, David Beierl <dbeierl@attglobal.net> wrote:
> 
> At 05:05 PM 1/6/2016, Richard Golen wrote:
>> for a couple of minutes. Drove home and then disconnected the wires to the O2 sensor. Took the van for a drive. Ran like a champ for about 5 minutes, and the loss of power, rich running, etc. started up again. This is the first time its run this way with the O2 sensor disconnected.
>> 
>> 
>> When it "idles" its runs roughly at 300 rpm and puffs out black smoke. I've blown through 1/2 a tank in 80 miles.
> 
> Find and clear the short to ground of the sensor wire.  It's probably where the shield ends on the bright green wire.  The insulation tends to crack there because of the sudden change in stiffness, and it get shorted by loose strands from the shield.
> 
> You should have about 0.45 volts on that lead with ignition on and sensor cold or disconnected, measured with digital multimeter.
> 
> Yrs,
> d
>