I had a CEL a month ago and was told two of my coils were failing. I had all 4 replaced since doing so only added a $100 to the cost. Since installing the new coils my mileage has gone from an average of 17/17.5 miles per gallon to an average of 20.3!

My 04 when new was getting around 20 (if I am remebering correctly) then after all the flashes it dropped in to the 17's.

Hope this is useful.

 

What were your symptoms of the coil failure? How many miles, hot or cold climate, etc.

 

Gotta join Mazda Motorsports. All it takes is doing two AutoX's a year. All four would have cost you $80.

 

Lol, the coils are less expensive than the spark plugs

 

unless you go to www.sparkplugs.com and buy the NGK plugs, they'll cost $19 each. if you get the denso plugs, it'll cost $35 each.

yamajj

 

I know there's a TSB regarding the coils. Here's my question: if my car is running normally, and I've never had a CEL, can I assume my coils are ok?

 

that's a good assumption i suppose

what's the old saying, 'if it ain't broke, don't fix it?'

 

and for the record my '04's coils are still fine, still averaging just under 19mpg in mixed driving, though I may replace the coils anyway when it's time to replace the plugs just as part of maintenance