bad coils
 

VERY FRUSTRATED" First and Last time I buy a mazda" owner!!!! Took my 2000 millenia S in to mazda once again for the same problem. My check engine light was "blinking", was told by mazda that one of my pistons was misfiring because of a bad coil. Had it replaced $800 later. Not two miles down the road the car started acting exactly the same way it was before it took it in. Once again I had the mechanic look at it, this time it was cylinder 5 that was misfiring because of a bad coil. This is the second mazda service center I've taken it to with the same exact results with the different coils. Last time it was coil#4 then it was coil #1; when will it end? If anybody has any idea what could be making these coils go bad, any info would be much appreciated. I definitly know that mazda has no clue.

RE: bad coils
 

Heat!!! [sm=badbadbad.gif]Look at where they are at and how much cooling air ciculation is available

RE: bad coils
 

heat is the weak point of the cop system. bmw STILL has a big problem with coils. dealers are changing out the coils in droves. the 92 M50 motor was the first to use the cop system, now all bmw's have it. on the early cars, if 2 or more coils went out at the same time, it would also take out the ECU(we call it DME), AND the abs control unit, about a 3500.00 bill. on our black car, which the wife drives, i went thru the same thing. first, random misfire, then 1 coil, then another. since i cannot take the chance of my wife being stranded on the road, i changed them ALL out, and the problem went away. i had to get all 6 from mazda, and it was pricey(i think they cost me about 135 ea, with discount) since then, i have gotten a set of used coils off ebay, tested them all by installing them on the white car, and now i have a spare set. i bought another set off ebay for only 20 bucks(6 coils!) used, and i even got a brand new one in the box for the same price. i like to have spare stuff, and i know the coils are a weak point. for 20 bucks, cheap insurance(we have 2 99 S'). it is not a hard job to get at the coils/plugs, but it takes time.