Could be your tires too. What tires are you running?

 

With stock gears, you should be moving at approx the following speeds at 4,000 rpms.

1st: 19 mph
2nd: 29.5 mph
3rd: 41 mph
4th: 52 mph
5th: 62 mph
6th: 74 mph


easiest to test in 5th or 6th gear.. if you had say 4.77 gears, the numbers will be way off up top.

 

Could be your tires too. What tires are you running? Some no name, cheap brand that haven't had the right testing can lower your MPG. However, I doubt it could lower it that much.

 

For comparison, I averaged 24.4 mpg in mixed driving (60/40 city/hwy) on my first s2k (MY02). I owned it for two years, bought it with ~39k miles and sold it at ~49k miles, and I kept track of mileage for every tankful (~40 fillups or so).

Lowest tank was 22.4 (winter, more stop and go than usual) and my best was 28.1 (almost all highway, driving to and from the beach). Engine never burned oil, and I drive my cars pretty easy so I'm guessing that helped. Not sure what these people do to get mileage in the low to mid 30's though

Hope this helps and GL

 

make sure you dont have spring spacers.

 

Ok sorry to bring my post back from the dead, but here's more info:

1. My speeds are almost dead-on to VTEC9's specifications. I think it's a standard diff.
2. I have Falken's in the front (type I forget, Honda recommended) And Bridgestone Potensa Pole-Position's in the rear. All stock sized (for AP1) and on stock AP1 wheels.
3. When idling, I'm noticing that the engine runs a bit rough. In any other car I'd say it's missing a cylinder - on an S2k, I have no idea. Once you give it any gas, it goes away. I'm thinking perhaps plugs, throttle body (do I even have one? lol)

Excuse my noobish questions. Most of my car knowledge comes from restoring old vehicles, and working on 4x4 trucks. (Can you tell I'm from Louisiana now? )

 

Have you adjusted your valves yet?

I was getting bad mileage on my '03 also, and the engine lacked the power it once had - it was so powerless I couldn't even chirp the tires going into 2nd gear. A friend of mine (who is a mechanic) adjusted my valves when I hit 100k and told me that the valves were way too tight (weird I know, but for some reason my valves got tighter, not looser). After the valve adjustment the power returned to normal and my gas mileage went way up.

 

I have a 2002, w/73k miles and my numbers are almost identical to johnjp27's. I think these tend to be the more common #'s for our cars, not the 30 or better #'s that some have reported. As others have said, check tire pressures, and find a better alignment shop.

Personally I never take my car to a dealer for an alignment. I go to an alignment shop. Recently I've had my best results using a local shop that sets up race cars. They hit my alignment #'s PERFECT (I us UK spec's) and did the best tire balancing I've ever experienced in 40 years of driving..

Finally, I would NOT recommend a CAI, esp. for your area. Do a search, and you'll find that people have had trouble sucking up water during bad rain storms with some of the units out there..

 

Did you try unplugging the battery for 30 minutes and then letting the car idle for 5 minutes to reset the ECU? Just put a K&N FIPK on and that's what it wants you to do.

Also, I just got my car from Carmax. I don't know the stories on the other S2k they had in the showroom, but one didn't have VIN numbers on the front bumper. I was just trying to compare bumpers on mine which was newer to another to see if there was anything funny. Seems logical to change some of the maintenance items since we don't really know how the owner drove the car beforehand. Though a valve adjustment makes the most sense.

 

Thanks for all of this good input. I'm going to find a better alignment shop, and get these valve timings looked at. I'll probably replace the plugs and wires just to be sure.

Now all I need is money!

Question to those of you talking about tire pressures: What do you recommend?