The car:

1987 N/A with RB headers, RB catback, with just the stock main cat bolted up between them. I don't have the o2 sensor extension wire yet, so I did a bunch of driving with my o2 sensor disabled. Mostly highway, but there were a lottt of traffic jams with stop and go.

So if I got 24 mpg with the o2 sensor not functioning, will I get roughly 5% better once its wired up again?

All of you people that get 15 mpg either rev the absolute **** out of it or need to fix something

 

You should get between 25 & 26 with a good O2 then, assuming exact conditions are repeated.

Accelerating the car (the way WE like to) is what eats up all the gas.

This engine LOVES fast cruising speeds (75-85 mph). I drive at about 3500 RPM for 35 miles straight 5 days a week (unless the DAMN trucks get in my way), and she purrs the whole way (and growls when I downshift to pass the DAMN trucks, lol)...

 

Not bad. Make sure you put a *working* O2 sensor on - get a new one if you haven't replaced it, they're cheap enough.

I personally was getting 22-26mpg in my 88 NA with gutted cats & non-working 6th ports. 26 was in a tailwind. I'll have new numbers soon with a rebuilt engine.

-=Russ=-

 

I'm pretty sure the o2 sensor is working, since the car passed emissions a few months ago. Before doing the math, I was a little worried after reading so many horror stories with miserable mpg's.