Symptoms of a bad 02 sensor on 94ss

[Damon]

What are some of the simptoms of a bad 02 sensor? I'm having some issues in boost and the car is sucking down gas. I'm getting roughly 20mpg. Could it be a bad sensor? I also have some stuttering/hesitation when boosting, it's not fuel cut it almost feels like something is holding the car back. Replaced the engine last year and this one feels just like the old one. Can't remember if I replaced any sensors or not when I swapped.

[FundamentalyConfused]

Did you verify all your grounds are connected properly without corrosion? Bad ground connections can cause lots of symptoms.

[Damon]

I'm going to look into that. Where are most of the grounds?

[Legacy777]

Here are some of the wiring diagrams for the 92 Legacy, but should be the same for the 94. Not everything is in there, but the main stuff about the engine wiring is.

http://main.experiencetherave.com/subar ... lectrical)

The ECU ground is on the back of the intake manifold on the driver's side down near the injector fuel rail. I'd check that first.