ok, i'm sorry to bother about another o2 sensor question. i have noticed that my fuel economy has started to dip down on my '97 4runner v6 sr5. my engine light finally came on and i didn't write down the code but the description stated that my o2 sensors had a slow response. so i am guessing that i need to replace my sensors. i'm just curious where i should purchase them, advanced autos has one for 89.99, napa has one for 111.99. any thoughts?

 

Only replace with denso...there are many threads on here about that topic just search a bit.

sparkplugs.com has good prices on denso o2 sensors.

 

Also, check your cats. Make sure the honeycomb isn't damaged or melted. If a cat is failing, it will give incorrect O2 readings. It would also indicate a problem in the engine, ie running too rich or too lean.

 

Go here to get the correct Denso part number and a decent price. For a better price, search for that part number on Amazon.com. Get the correct number first, Amazon's application info is sketchy at best. You can Google "Denso XXX-XXXX" using the number and check prices everywhere.