where is the oxygen sensor located on an 83 rx7 gs
im looking to replace it if nessecary since i get such bad mileage
also how hard is it to do this?

 

There isn't one, its not FI, the ecu doesn't control the carb.

I'm definately no expert on carbs, but the carb could just need a rebuild.

 

i get about 250km to a tank at about 50 litres, at 40.00 canadian
is that bad?

 

250 km is 155.3 miles, and 50 liters is 12.9 gallons (?) ... so 155.3 divided by 12.9 equals 12 MPG (if my math is correct).

Is that highway driving, or city driving? Short trips, long trips?

 

that is only city driving

 

I get 200 miles to a tank in the city (50 miles perhash mark), and 14 gallons at a time . Today for the first time ever the pump actually put in 15.003 gallons. First time Ive ever seen it take more than 14 gallons. It was damn near $22 too, lol. I normally only put in $18-$20 depending on price, but its usually right around 14 gallons . I drove out a whole tank nothing but highway, (I-90 east to Central University if anyone knows my area) filled her up before I left, got there, came back and still had half a tank after 228 miles round trip . First time I ever saw my trip meter over 300 miles on one tank...EVER. My dads -SE gets 300 per tank everytime though, 75 miles per hash mark

~T.J.

 

my SE got 340 miles out of this last tank of a long raod trip (only 270 out of the 1st 4 on the trip, not sure why the 340)

well, on the other hand I did put 15.6 gallons back in it as well...

I could get 400/tank easy on my 85 -SE with the taller 5th gear. 27mpg was my personal record.

 

Yep, that gas mileage is crap. Do you have a modified carb setup?
If not maybe your secondary's are stuck open (if you have a stock carb)

 

completely stock carb
i wonder if a rebuild might be in order.