I have basically been getting bad gas mileage since I bought my Miata almost a year ago. I wasn’t expecting to be driving a hybrid, but 18 mpg just seemed a bit too low for a 1.8l, even if it is a “little” sporty. I set about trying to make it run better and more efficient.

I basically did all the maintenance stuff (plugs, air filter, pcv valve, gas filter, plug wires, oil change, and transmission change. I also replaced a bad 02 sensor. The car felt much better, but I didn’t see much of an increase in MPG.
I had all but given up.
However, a couple of weeks a go I replaced my worn out engine mounts with Mazda Comp Mounts (the biggest pain in the butt job I have done so far). Not only did I have better shifts, the car seems to maintain speed much better when I let off the gas. Before, it would slow down like I was slightly hitting the brakes anytime I let off the gas. I think it had to do with the engine not lining up well with the transmission because of weak/ripped engine mounts.

So if you are getting low mileage, first do all the regular maintenance stuff. But if that doesn’t fix it, and you have a loose motor (shifter moves when you hit the gas) then you might consider replacing your motor mounts. It made a big difference for me.

  1. Corolla says:

    This is a really good summary of the best sites out there- I’ll be linking to this on my blog. Thanks