some questions

[sloopy]

i was wondering if anyone could tell me where the number one o2 sensor is located. also i have the original timing belt @ 125k if this belt breaks will my engine be ruined or is this a non intrusive engine?

 

[RonMAIDEN]

3.4 is a non-interference engine.

 

[sloopy]

sweet so i really dont have to worry about the timing belt. my 4runner started making a grinding noise from the rear, so i changed the fluid, and greased all the zirks but i am still getting this noise.?.? i know its not the breaks because i jacked the rear and the wheels spun freely.

this is my second 4runner and i never had any problems with the last one, except rust.