How can you test O2 sensors?

C

cobra98lsc

Registered
I have no trouble codes but my mileage is down in the teens on the highway even with the 4.10's i always got around 24mpg

Now i am down to 18-19 mpg
Changed trans fluid
Cleaned MAF
Cleaned K&N
Changed and gapped plugs NGK TR6
Back to stock t-stat from 170 no difference
Motor sounds good except for a small exhuast leak i have gotten on the driver side that might be the EGR pipe... i havent checked into that yet.
I have NO EGR
Cobra Intake
Dual 3" no cats
4.10's
Doesnt use a drop of oil i have run Mobil 1 5w30 since 5000 miles new
I am out of ideas other than the O2's
Also i did pull the chip out that Jerry did a few years back to match my 02 LMAF and the motor doesnt run good due to the wrong MAF table but the mileage jumps from 18 up to 27mpg when cruising.

I have 130,200 miles on the original O2 sensors.

Are they shot? I hate to waste more money on them if not gonig to help.
 
RE: How can you test O2 sensors?

..."130,200 miles on the original O2 sensors"...

With that many miles why even ask. They are a wearable part, just replace them. I did mine at 80k and the car ran much better.
 
RE: How can you test O2 sensors?

I was also wondering if the lack of an EGR would cause a drop in cruise mileage?
 
RE: How can you test O2 sensors?

Welp they are like 70 bucks each at Oriely for a Bosch OEM type.

So for 150 ish i can get some mileage back.

Guess at this point its worth the money for saving some fuel.
 
RE: How can you test O2 sensors?

Your timing must be increased a lot by the chip if you lose that much milege with it. I would get new 02 motorcraft sensors for best performance.
 
RE: How can you test O2 sensors?

Yeah i kind of wondered about that myself.

But for longest time with this tune i got 24-25 hwy

Timing shouldnt change

I even replaced the crank sensor

How to test cam sensor?
 
RE: How can you test O2 sensors?

O2's rarely last 130K miles, especially with some mods to the car. They're only $50 each, but a PITA to replace.

mark
 
You must log in or register to reply here.
Back
Top