Missing O2 Sensors?

[lj80]

Guys
Went searching for the location of the O2 sensors today. I checked the pictures out online of the locations and I cant find them.
The car is an 2001 wrangler.
There is one sensor down near the bash plate. There are two holes just under the exhaust manifold where I have seen the O2 sensors in pictures but the holes have grub screws in them. Is this going to cause a problem?

[Jeeps]

I only have 2 sensors on my 2002 TJ. One near the t-case and one up higher near the manifold but not all the way up.

cheers

[lj80]

On the exhaust or on the intake manifold? there is one that looks like an air sensor on the intake but there is only the one on the exhaust side.

[Jeeps]

Mine are all on the exhaust side. You might be thinking of the air intake sensor, some are mounted on the air filter tubes but most, like mine, are mounted on the manifold.

cheers