I have had a private garage replace the spark plugs and wires last year and noticed performance improvements. This spring I had them replace the engine ignition coils. All were with fully certified after market parts. Almost immediately my engine light came on. Worried it was something big I went straight to Mazda. There charged me 100 dollars to say it was an engine misfire replace plugs, wires, and coils. I said have you looked! All are new. They then insisted that non Mazda parts were not good enough specs and this was the problem. Is there any merit to this?

 

If it were me I would put mazda brand coils on my own rx, just for peace of mind. I work auto parts and seen too many times aftermarket parts just do not compare to stock. If the engine light came on just after replacing the coils, take them off and put oem back on.

 

Your best bet is to check the coils and plugs to see if they are correct.

 

Yeah, I'd first check to see if the plug wires are secured on both ends, and are in the right wire order. It's the most likely reason for an immediate problem after an ignition change.

Otherwise, what brand were the coils? There are definitely some brands that work well, others that don't at all. I have never seen any coil brand "certified", which makes me wonder if it's a fraudulent claim.

 

Thanks for all the suggestions. I was lose with language and did not mean 'certified' but oem parts from a reputable parts supplier. I was hoping that Mazda would actually look at the car and as part of diagnostics give it a quick look over and check connections rather than use a diagnostic code and blankly state you need plugs, wires, and coils because we don't show a record of having replaced them. Paying everyone here for bad service. It should not be so complicated!

 

To a dealer it isn't complicated, they just throw parts at the car since diagnosis takes time and doesn't make money.

It doesn't help anything when you learn that the dealer's actual test methods for the ignition won't detect a failure.


There are other reasons for misfires, and the timing could be coincidental, if your wire order is correct and all wires properly secure.