Horrible running 8v

[spewey at comcast.net (Spewey)]

Jason Peters wrote:

> Hello everybody,
> 
> I'm pretty new to the 'rocco list so excuse me if this is an easy 
> question/fix.  First a little background: '83 'rocco 8v on CIS
> 
> I replaced the O2 sensor with a nice new one, connected it and fired
> it up.  Seemed to run fine for the first few minutes(maybe till the
> sensor warmed up) after that the idle started to hunt around up and
> down.  Backed out of the drive way and the car would barely go.

Welcome!

1. Those one-wire sensors only warm up from exhaust heat.  Three-wire
sensors have a heater in 'em. Ones would perform worse when cold if
everything else is good.

2. They need a good ground/shield.  It's a milliamp signal.  Make sure
all connectors are intact.

3.  If it runs better without it, do that until you find the mixture
problem or the plugged cat/muffler (or, I guess, bad ECU).