Should I replace my o2 sensors?

[JTR 97 Z71]

Hello,

 

I have a '97 K1500 and have been geeting worse gas milage than I used to for about the last 25k. (I used to get about 17/19 MPG, now it's 14/17). It's at nearly 130k now, and It's still on the origional O2's. Should I change them? -I've never had o2 sensors last over 70k miles before, so I'm sorta suspisious of them. (Of course, I've never had a cat last over 79k before either). I replaced the plugs, wires, cap, and rotor at 105,105,120,120k respectively.

 

Thanks,

-Justin

 

EDIT: Actually. . . I haven't replaced the wires. . . They were out of stock at the time and I figured I'd do it later. . . hmmm. . . I just remembered about that!

[C & A s Dad]

I am no technician but I can tell you that replacing the 02 s has become a part of most good tune ups. With your miles, I would say they need replacing and you will likely see a dif.

[getcrunk88]

i would most definatley replace your o2 sensors pay for themselves in not long at all

[JTR 97 Z71]

Thanks guys, I'll replace them as soon as I get back.

 

My truck should have four o2 sensors, two front and two rear, correct? Anyone have the part numbers by chance?

 

Thanks,

-Justin

[OnyxMAX]

if you have a ossicilascope or volt meter with a bar graph you can check um.

 

i have noticed as fuel prices climb i get worse mpg.

 

should get around 500mV+ cold and then as it gets warm and runs into closed loop should begin to switch low high rather quickly 100mV to 900mV if it sticks below 500 or over 500 replace it or switches but stays on one side for a while. the post cat ones are for show and realy just trigger the mil if the cats dont work the should read steady but i forget their range.

 

didn't notice fuel filter on your list of replaced items.

 

i'm gonna go with bad fuel they been selling and prolly a O2 reading constantly lean, but not setting a code since the post cat is reading clean. if you got the dogh or access to a scanner you can pull up the O2 readings and check the fuel trims.

[Jim2002Z71]

Have you also tried cleaning your MAF ???

 

Use CRC MAF Cleaner..P/N 05110 ($5.99)

 

Spray on..let dry, reinstall...I used almost a whole can...works better..better throttle response.