which o2 sensor do i put the antifouler plugs on and how many

[brad5428]

which o2 sensor do i put the antifouler plugs on and how many?i have one on the intake manifold and right after the cat.

[Erik]

One should go on the exhaust manifold- not the intake

[brad5428]

i meant exhaust not intake.what about the 2nd o2 on the cat?

[Erik]

IMHO the most important one to put the extender on is the one between the engine and cat, as far as I know, its not a bad idea to put the one on the post cat sensor as well.

[Ratman667]

IMHO the most important one to put the extender on is the one between the engine and cat, as far as I know, its not a bad idea to put the one on the post cat sensor as well.

i agree if you put one upstream, that sensor will send one signal, and the sensor downstream(after the cat) will expect a certain change. unless you have identical setups on both sensors, then it will more than likely throw a code.

[Ford Man]

I remember reading somewhere that they shouldn't be used on the downstream sensors, but don't remember where I read it so I have nothing to back that up. I can't even remember what the reason for that was. I have heard of people using one per sensor and have also heard of people using two per sensor to move the sensor further out of the exhaust stream.