Mazda Repair: 99 Miata Engine Misfire, spark plug wires, ngk spark plug wires

Question
QUESTION: I recently read a question you answered by Greg regarding his 99 Miata and random misfires.  I too am having the same problem.  My Miata has 19400.00 miles.  Yes - 19,400.00 - not 194,000.00. miles.  I purchased it new ten years ago.  I have had it in and out of four different shops since this began in October last year.  

I have replaced the plugs and wires.  I have had the rails cleaned.  I am being told that the computer is giving out random codes to my mechanic's computer and sometimes not communicating at all.  

The Mazda dealership here who has had the car four different times suggested that we replace the ignition coil next - but could  not guarantee that that is really the problem. Can an ignition coil randomly fail??

Is there a chance that this is a computer failure?  I'd love to know your thoughts.

Thanks,
Leigha

ANSWER: There is no giant mystery with your Miata - no lemon issue just a bad coil and technicians who are not familiar with the Miata.  

The ignition coil assembly has been a common problem with 99 and 2000 model Miatas.  Yes, they can fail intermittently.  The most common code is random misfire, determine which cylinder is misfiring and write it down.  I suggest a new set of NGK spark plug wires and a new set of NGK spark plugs first, consider them preventive maintenance.  If the problem re-occurs then order a coil assembly and have it replaced.  (Save to old coil assembly it's worth about $30 to us as a core)

service@miatashop.com

---------- FOLLOW-UP ----------

QUESTION: Are you serious!!! I'm over $500 into this and the car is still not running right.  If this is a known issue for this year/model did Mazda ever consider a recall?  I'm going to do as you say and get it replaced.  I've been in touch with Mazda customer service numerous times and they never told me that this was a known issue.  Makes me never want to purchase another Mazda again.

Answer
Sorry you've wasted money hunting a ghost, it's because you didn't find me before hand, but now you know who to ask in the future, right?.  As for the purchase of another Mazda, considering you have 19k on a '99 Miata and given a Miata's reliability and longevity you'll be having no need to buy new for a good long time.  It's man made, things break.  It's also nice not to have a car note, isn't it?  See you when you have 194k on that odometer.

Be sure to get the MIL (malfunction indicator lamp) read, recorded and cleared.  It's important to know (I know and you know) what codes the OBD2 system is giving, as for a technician not being able to read the codes, well then he either isn't using the right tools or there is no codes in the system.  If the MIL is on or came on then a code will be in the systems memory.

If you can't find a good Miata technician or specific shop there then your welcomed to visit us in New Orleans any time.

service@miatashop.com

"If your good at what you do, you should be well paid for it"