SPS

Oops my bad I meant to type 29mpg. My old saturn (92 SL1) got 40mpg on hwy. I wish I could get that out of this one.

OK, well 29 is lower than the EPA rating.

You could always try making a few changes:

1. Top off the air pressure in the tires. A little more pressure than spec will improve the mileage, but will also reduce your tire contact patch - which means less traction in the corners and less even wear patterns.

2. Do a basic tune-up including: fresh spark plugs and fresh plug wires, clean or replace your air cleaner, change the oil.

3. You could have some debris negatively affecting the injector spray. A bottle of fuel system cleaner is a cheap and quick way to do a rough cleaning.

4. You could have any number of engine management sensors that are starting to wear out - though typically you will get an SES light when their voltage gets out of range. But a new oxygen content sensor in the exhaust manifold could help. Also the air intake temp sensor in the intake.

Hmmm...actually that gets me wondering. What kind of intake kit do you have? A good one that includes a fitting for the AIT sensor? Or a crappy chinese unit from ebay? If your AIT sensor is not plugged into the intake pipe, then your engine is not running efficiently and this could explain the loss of power and the poor mileage.

5. Try being really conservative with your foot for a tank. Most Saturn performance enthusiasts (including myself) tend to use the throttle much too aggressively. Racing up to speed from stoplights and accelerating quickly out of corners kills the fuel efficiency. On the racetrack, we averaged about 8 MPG...

All of this discussion about fuel economy made me realize that I can't really remember the S series ratings anymore. And even if I could, the new revised EPA standards result in lower ratings now anyway.

So I wrote a new tech article with an updated chart comparing all S Series fuel economy ratings using data that I got from the EPA site at www.fueleconomy.gov.

Check out the article and the comparison chart here:
http://www.spswebpage.com/Tech-Article-Archives/Fuel-Economy-Ratings-for-the-Saturn-S-Series.html

FYI, the modern EPA ratings for the 98 DOHC are 23/33 with a manual trans and 21/31 with an auto trans.

Wow I thought I was supposed to be getting 34 on the highway but it looks like I'm sitting right in the middle and should not complain. Thanks for researching that, takes a little worry away.