O2 Sensor Effect?

[Hutch998]

I have a 94' GMC Sierra 2500, 5.7 350ci. A while back the o2 sensor was taken off, but never replaced. How much does this effect my mpg? I figure its about 6.5-7mpg as is now. If I add one, how much will it boost my mpg? Also does anyone know what o2 sensor this truck takes? (2 or 4 plug).

 

[magimerlin]

It will help alot.... as to 2 or 4 wire. Look underneath the truck and see what plug you have....

 

[Hutch998]

Alright thanks!

 

[magimerlin]

I say look underneath for one simple fact...... my 94 C3500 has (had) a 2 wire and my 94 k1500 had a 4 wire... both are the same exact motor...5.7tbi.

 

[Fredridge]

I took my first long trip in my k1500 blazer.

my check engine light was on for part of the trip out.... I got 14mpg

had it and fuel filter replaced and in the way back I got 16mpg

that was with it only partially having issues

 

[poncho62]

With no O2 sensor, your computer goes into a rich fuel mode to be safe......O2 sensor helps lean it out as needed, so of course it is going to help mileage