1994 Corolla With 23 Miles Per Gallon Only

[natcire]

I forgot to add to the previous question.

I also have an automatic 1994 Corolla that is only getting 23 miles a gallon in mixed city and freeway driving. I had a manual 1983 Corolla that got about 34 miles a gallon in mixed city/freeway driving.

Any ideas? I have had the car "tuned up", oil changed, air in tires...etc. Could a new set of spark plugs do better? The tune up did not include new spark plugs.

Thanks, again, for any assistance.

Eric

[Pablo 23]

:bookworm:

Yes, new original spark plugs are a must, as well as new spark plug cables, distributor cap, rotor, air filter, fuel filter, pcv valve, maybe cleaning the fuel injectors professionally (between $75-$100+), correct wheel alignment and tire balance of all wheels, check the ignition timing and set it correctly...and...this should be done by a good mechanic.

There might be another problems, but only seeing the vehicle is possible to check. Other than that, be sure you are calculating the average fuel economy correctly.

I can't think of anything more right now. I forgot, the idle speed has to be set correctly too, using equipment, to the factory setting. Actually is a idle adjusting screw what needs to be move, but you have to know the rpm with equipment. A SIMPLE OR LITTLE MOVE COULD BE TOO MUCH and the rpm at idle speed might climb too much or be too low.

One more thing: a real tune-up, by definition, includes replacing the spark plugs on any vehicle. If the spark plugs were not replaced, no tune-up was really made.

Good Luck