O2 sensors

How many O2 sensors does s 2001 taco pre runner 2.7 L have?

 

2

 

One Air fuel ratio sensor (upstream) one oxygen sensor (downstream)

 

Pre and post cat is another way to think of the two. It's how cat efficiency is measured.

Been that way on every single cat exhaust vehicle since OBDII started in '96.

 

2001 and up have 2 cats for the 1st gen's

 

On the 2.7? All models, or Cali models? (I don't know)

If 2 is it a Pre cat and main cat?

My V6 has 3 sensors, one in each bank and one after the cat, but the OP was about the 2.7. My '13 2.7 only has one cat and two sensors.

 

Yeah on all the 1st Gen models (2001-2004) 2.7 and the 3.4.. First one is a pre cat, then the main cat.. The 95-2000 only had 1 cat