I just bought a 1991 Cutlass Ciera witha 4 speed automatic and the 3.1 four cylinder engine. I have been averaging 26-27 mpg for the first several tanks and I fel I should be doing around 31-32 mpg. I am very carefull about accelerating slowly, etc. What kind of mpg figures shoild I be expecting? I do 90% interstate driving.

 

Don't know what the advertised mileage was when it was new but what you are getting doesn't sound too bad to me. I get 21 in the city with a 1999 3.8 liter GM sedan.

 

I agree.

My 2000 Alero with the 3.4 is getting 20 MPG combined city and highway. but all highway I'll get 35 which is better than the advertised mileage of 32

 

You might want to do a tune up on the car if you feel you are getting poor gas mileage. Make sure it has a good air, and fuel filter. You should also make sure the ignition system is in good shape. Replace those spark plugs and spark plug wires. Finally, you can remove the throttle body and desludge the backside along with the idle air bypass motor. I do this on all of my newer cars that I purchase used. It seems to help. It is amazing how much a small piece like the idle air bypass can affect the idle of an engine.

 

I have the 3.1 in my little 90 buick coupe. I get 32 mpg on the highway, but my car is tiny. You have a 4 door, probably heavier.

 

I had the same car for about 3 years and never did better than 30 MPG 26-27 was normal.