Whats are signs telling you that the O2 sensor is buggered?

On the 4 cyl efi is the O2 sensor the one with the wire that goes through the exhaust manifold heat sheild?

Can you tell by visibly inspecting it that its buggered?

with mine i had a ruff idle and the car will stall sometimes. I changed the O2 sensor for $100 and gone whet the problem. I had 3 different mechinics look for the problem and one of them found it my local mit's service centre :D

i have 94 ts v6 and the 02 senser conected to the exzorst (just under the centre console)
and as far as i know the wire going through our heat shield like u said is your 02 sensor (read somewhere but can't remeber where :doh: )

when our O2 sensor went we had the check engine light come on cost us $80 for a new 1 to be put in.

needs to be checked by a fluke 98 or a osiliscope

Whats are signs telling you that the O2 sensor is buggered?

On the 4 cyl efi is the O2 sensor the one with the wire that goes through the exhaust manifold heat sheild?

Can you tell by visibly inspecting it that its buggered?

One sign is a fault code for the 02 sensor. have your checked for any fault codes?

"most common cause of failure in an O2 sensor is contaminants, which are always present in the exhaust as carbon and probably unburned oil."

Also:
Rich or Lean fuel condition
Reduced HP
Reduced gas milage
Unstable idle

First photo of my old down pipe 02 sensor and the new one.
Seconf photo - more photos