98 coupe 66k

My fuel consumption went down to around 10mpgs and i put a bottle of 12 gallon techron injector cleaner in . Im up to around 12 mpg . Im bringing my car into chevy to do new spark plugs and wires ,fuel filter and fuel regulator ..any ideas what else to change for maitnance?

[Speedratchet]

I would have them check the performance of the 02 sensors.

[JBsZ06]

my gas mileage blows too..

I'm even lower.

It could be I'm reving to redline at 80% of my shifts but I'd be curious how you check the 02 sensors performance?

Can a GM dealer use the tech II to tell if the o2's are operating properly?

or is there some other meathod preferred?

any insight would be appreciated.

[ToolGuy]

I am sure the dealer can use a Tech2 JB on the O2's. I have never done this to know what to look for myself when I use mine though but it has to be in the engine data screen that watches RPM's, open or closed loop, fuel and things like that.

Jay, I would throw a new PCV on your car too if you have not done so. It is cheap and at least you know it would be new.

[Speedratchet]

Originally Posted by JBsZ06

my gas mileage blows too..

I'm even lower.

It could be I'm reving to redline at 80% of my shifts but I'd be curious how you check the 02 sensors performance?

Can a GM dealer use the tech II to tell if the o2's are operating properly?

or is there some other meathod preferred?

any insight would be appreciated.

A lab scope is the best way to check the 02 sensors. IMO

Most computer systems monitor the activity of the O2 sensor and store a code when the sensor's output is not within the desired range. The normal range (front 02s) is between 0 and 1 volt and the sensor should constantly toggle from close to 0.1 to 0.9 volt, then back to 0.1. If the range that the sensor toggles in is within the specifications, the computer will think everything is normal and respond accordingly. This, however, does not mean the sensor is working properly.
The voltage signal from an O2 sensor should have two to three cross counts with the engine without a load at 2,000 rpm. A cross count of an O2 sensor is the number of times the waveform moves from a high voltage and back to that voltage.
Remember that other malfunctions can give you a bad reading.

[JBsZ06]

Wow..

Thats quite an answer.

Thanks.

Is this a normal dealership procedure in checking an 02 sensor at the request of a customer?

TIA

JB

[Speedratchet]

Originally Posted by JBsZ06

Wow..

Thats quite an answer.

Thanks.

Is this a normal dealership procedure in checking an 02 sensor at the request of a customer?

TIA

JB

I don't work at a dealership, so I couldn't say.

[JBsZ06]

Thanks I'll touch base with the tech.

Great information and its appreciated.

JB

[aquaholic]

a bad 02 sensor in my toyota took my gas mileage from 31 to 20.

[JBsZ06]

I put one can of seafoam in the gas tank...ran it through...

Then the next tank....did it again..

Cars running much better!

Gas mileage can pick up.

Confirm avg speed to avg mpg...

Still good to check o2's.

Great info on thread...