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Appropriate mileage for a '99 Miata?

Hello there,

I was hoping the wisdom of CarTalk could help me figure out what the appropriate mileage (miles-per-gallon) for a '99 Mazda Miata with about 65,000 miles on it would be? I’ve been keeping track when I fill it up and saw that it was only getting 18-20 mpg with 75% city driving. Is that average for this car and this age? Or is this more of an indication that there is something off with the engine but not so ill-performing as to cause the check-engine light to come on.

Thanks for any insight.

p.s. What is up with the message board only allowing a choice between Mazda models 626 or 929?

Click on the link. You didn’t say whether you have an auto or manual transmission, but it’s about the EPA estimate for city driving and slightly low for a manual transmission. Try other years in the same generation (1999 to 2005) to get additional information. If you click on “show details” in the highway mileage block, you will get a pop-up. click again on “more information” to see reported mileages from isers and their % city/highway. Remember that how you drive has an effect on your mileage. Lots of quick starts will lower the mileage. Since I don’t know you, I think it’s imortant to state this.

I should have found that site quicker. Thank you!

It is a 5-speed manual. My wife and I aren’t aggressive drivers, so I was expecting better mileage than what we’re currently getting. That page indicated the “real-world” average was actually 29 MPG, but I don’t know where that data is coming from. If that’s accurate, we should be able to increase our mileage but up to 50% with better driving and finding possible problems. It was her car before we got together and I think she’d done all the regular maintenance, but maybe something was missed.

The worst mileage reported was 24.5 MPG in North Carolina for 80% city and 20% highway. Do you have a lit check engine light? What is the tire pressure, and what does Mazda recommend (see driver’s door placard)? When was the last time the air filter was changed?

You might want to be certain that your engine is getting up to operating temperature. Mazdas are great cars to drive with the top down and often a person doesn’t notice that the heater isn’t putting out much heat–a symptom of a thermostat that is stuck open. As another post suggested, check your tire pressure. As I remember, the Mazda Miata calls for premium gas. If you are using regular (87 octane), you may get lower mileage.

That does seem a little low. Unless you are doing nothing but stop and go traffic most of the time. Stopping a lot at traffic lights, etc.

You might want to take a long drive out in the country or on a freeway and see what it gets. If it is ok there, probably everything is ok.

There’s no harm done in bringing all the Mazda recommended preventive maintenance up to date – you know, what they recommend in the owner’s manual. If you haven’t changed the air filter in 2 years, or changed spark plugs is the past 30K, that’s probably the first place I’d start.

The 1999 Miata uses regular gasoline.

I agree with the suggestions about tires and the air filter. I have a 2002 and it doesn’t get great mileage in really urban stop and go around the San Francisco Bay Area. The suggestion to air up the tires, check the filter and take it for a longer ride makes good sense. By the way, my 2002 uses premium fuel, and it does matter.

These are small cars, but they have gearing that makes the engine rev pretty high in order to get the speedy performance we all love. The price is gas mileage. Just remember that gas mileage is only one expense in owning a car. The Miata is pretty cheap to own generally, reliable and fun. Yours is 13 or 14 years old and you are still using it.

Thanks for all the suggestions. According to the link above, the '99 Miata uses regular ('87 octane) gasoline. So at least I haven’t been making that mistake.

I asked the wife what kind of maintenance she had done one the car and she said she always brought it to a reliable mechanic friend for everything… until three years ago when she moved away from his area. Since then it’s been just oil changes.

This weekend I’m going to do as much of a tune-up as I can manage: oil change, transmission fluid, spark plugs and wires, air filter, fuel filter, tire inflate, etc.

I’ll let you know in a month if it improves the mileage much.

You may want to try 2-3 tanks of premium just to see if it makes a difference. If a change to use premium was made in the next model year,its possible yours may need premium. I have seen many a car/truck in change over years end up with parts from both model years. I once had Chevy Blazer with a 350 V8. It ran better and did alot better on premium verses regular.

I had a 2000 Miata for a few years and averaged around 30mpg, usually a bit over that.

The requirement for premium fuel did not come around until the 2001 model year when Mazda changed to the VVT engine.

Miatas of this vintage are sensitive to spark plugs and wires, unless you’ve changed to a “special” plug you should be changing plugs about every 30k miles and it may not be a bad idea to do wires at the same time. If you look at the Forum there are some very strong feelings about the brand of wires to use.

You mileage isn’t outside the norm of people on the Miata forum, although I consider it low.

Thermostat is definitely worth a check.