All,

I have a 1994 Accord LX-ABS with the automatic. It's got very low miles on it (about 47.5k as of this writing), and seems to run well, but it gets poor mileage (I've gotten between 22.5 and 23.5MPG consistently). I commute about 10 miles one-way to work, and it's a mostly flat straight highway. I'm pretty careful about driving a reasonable speed (between 65 and 70MPH), and am good about no jack-rabbit starts. When I first got the car about 3k ago, I switched from a larger SUV (a 98 Isuzu Trooper), and so I was "driving it like I stole it" -- many trips to redline, quick acceleration, spending more time at 85 than 65 on the freeway, and it got around 23-23.5MPG then. The Trooper got about 14-15MPG on the same trip, but it had oversized tires and it weighs like 5000 pounds. I put a new set of spark plugs and new air and oil filters (plus oil change) in my Accord, I had a professional shop adjust the valves, it has new Michelin X-Radial DT tires on it in the proper size and at the proper pressure, and seems to run good. However, it's still getting what I feel is lousy mileage. Am I expecting too much to see 28MPG on a mostly freeway commute? Or should I be looking at changing out a few more parts? I don't have any check engine lights on, fluids all seem to be fine (well, I am planning to change out the tranny fluid soon), no white or black smoke from the tailpipe, the usual things I can think to check are all covered. Would a new O2 sensor be recommended since it's like 15 years old now? Any other words of wisdom?

Thanks!

 

I drive a 94Ex (230k miles) on a 20 mile one way commute, w/ 1/3 suburban and 2/3 freeway miles. I average about 27-28 mpg per tank over last year or so.

I would suggest checking fuel pressure regulator vacuum reference line for fuel leak (any gas smell would indicate a failed FPR diaphragm (loss of fuel). Also check all the injectors for leaks from fuel rail to fuel injector. It can be difficult to spot a small fuel leak as fuel will evaporate quickly. Smell while shut down after fully warming, may be helpful to find any leak. Finally, I would replace the O2 sensor as it may be original and simply too slow response for best fuel economy.

Make sure all brakes are working correctly w/o excessive pad or shoe drag.

W/ reasonable driving you should get 25+ mpg w/ ease. I improved my mileage last year from 25-26 to 27-28 by restricting max rpm to 2000 rpm (60+ mph in high gear).

good luck