Poor Gas Mileage

[George Lopez]

Hello, I am a new member & need your expertise. A few months ago I purchase a used 1998 SL1 with 143000 miles from the original owner. A copy of the window sticker stated 27 City & 37 Hwy MPG but I am averaging about 17 MPG in strictly city use . The strange thing is that I get 35-36 MPG while cruising 70 MPH on the highway. The car runs fine but this poor city mileage is upsetting. There are no codes stored nor is the Engine light on. I replaced the ECTS, spark plugs, cleaned the TB, cleaned EGR but to no avail. Could it just be city driving or is something really wrong with the car. Please Help.

[amazinghl]

What city do you live in? What temperature are you getting?

[Gerry Proctor]

City driving is, at least, an obtuse classification. Specific driving conditions would be better. Consider this: In one case, city driving may be some traffic lights, but otherwise somewhat steady, but slow movement. While another may be bumper-to-bumper gridlock with long times just sitting still. In case one, there is some progress. In the other, a car gets zero mpg while sitting still. The fuel economy returned will be vastly different between these two "city" driven vehicles.

That you are in the zone for your highway economy, I would say that you are about right overall.

[George Lopez]

Gerry, the car is driven to & from work 10 miles a day round trip (About 50-60 per week) with some stops at the grocery store & several start ups involved. Currently it is 25 F in chicago.

[Gerry Proctor]

Originally Posted by George Lopez

Gerry, the car is driven to & from work 10 miles a day round trip (About 50-60 per week) with some stops at the grocery store & several start ups involved. Currently it is 25 F in chicago.

Again, is that 10 miles from one side to the other though the heart of downtown Chicago traffic at rush hour? Or is it something else?

I still don't see you having an issue, though, since your highway economy is pretty good.

I think your less than expected city economy is just a reflection on the driver and the conditions.

[George Lopez]

I live in Chicago. The weather at the time of purchase was about 50 F & I use premium fuel (93 octane). By the way, it is an automatic.

[bender]

Originally Posted by George Lopez

I live in Chicago. The weather at the time of purchase was about 50 F & I use premium fuel (93 octane). By the way, it is an automatic.

I believe it is generally reccomended to not use premium fuel. I doubt it would cause worse gas milage, but the Saturn engine is designed to take regular unleaded.

[wrenchtnr]

Your car is fine. Your 5 mile commute (in 25 degrees) is not getting your car to ideal running tempeture, that's why you are getting lower than posted MPG.

[amazinghl]

Originally Posted by George Lopez

I use premium fuel (93 octane).

Don't use premium fuel. 93 octane is really for turbo or high compression vechicle, which your saturn is not.

Save yourself the money and get 87 octane.

Your gasmilage sounds fine for the condition you're using it for.

[madpogue]

Could the high-octane fuel be confounding the PCM, coaxing it into some mixture/timing mode that yields lousy fuel economy?

[amazinghl]

His below freezing 10 miles round with many stops and starts in between hurt gasmilage more than anything else.

Using 93 will just cost him 20-30 cent more every gallon.