Misfiring between 2000-3000 rpm suggested all was not well below the bonnet of my 1996 Mazda MX-5. On one journey, fortunately close to home, the misfire was so bad that it was reluctant to move above 3000 rpm at all, necessitating a gear change to force the revolutions up.
I had a new set of NGK BKR6E-11 spark plugs sitting around waiting to be fitted, but they didn’t seem to make any difference, so the next things to look at were the spark plug leads (also known as high tension leads). If the spark plug leads didn’t make a difference, the next thing to look at would be a coil pack; at over £200, this would be getting costly. So, at about £30, it made sense to try changing the ignition leads first. Again, MX5parts provided the spark plug leads at a reasonable price.
As usual, changing them was a simple task, but here are the photos anyway. If you need further guidance, you might want to consider buying the Veloce Mazda MX-5 1.8 enthusiast’s manual, or alternatively the 1.6i enthusiast’s manual, should that be more applicable.:
You can probably see from the last picture that the leads are a touch on the long side for the MX-5; I suppose that’s the result of buying budget leads.
As far as performance goes, however, the engine seems much happier. Not had any misfiring yet, and the engine is a lot happier at low revolutions, allowing me to stay in a lower gear. That, I believe, is having a positive effect on my fuel economy: by my calculations, since changing the leads and plugs, I managed over 30mpg from my 1.8i for the first time. And that’s without any motorway cruising, albeit a bit of dual carriageway driving.
Your mileage may vary, quite literally; let me know how you get on!