what is the Lifetime of a set of 'plugs for RX8? How much does a replacement set cost? Last question is, what changes in performance signal bad plugs? 04 winning blue Rex w/71K+ miles would like sound advice to keep running well and having fun.

 

Moved to Series 1 Tech instead of Series 2 Tech, assuming you have a 2004 per your username.


Plugs get fouled up easily, some people replace them every 10-15,000 miles. Others replace with the coils every 30,000. I wouldn't trust a set of plugs past 30,000, and I don't have much trust even up to that point.


Fouled plug symptoms are the same symptoms as failing coils, failing plug wires, and share many symptoms with vacuum leaks, O2 sensor failures, low engine compression, and e-shaft sensor fouling. They also share some symptoms with grounding problems, MAF fouling, cat clogging, and failed motor mounts.

See my new owner's thread in my sig for details.

 

Hi, I paid $21 ea. For NGK laser iridium plugs from Advance Auto.

Have fun!

 

the scheduled replacement interval for the spark plugs is 37,500 miles, or 30,000 KM's, so this is the longest you can go.

 

You can get the plugs on Amazon.com for $65 shipped to you or you can buy at autozone/advanced auto/checkers and use some type of coupon to make them cheaper than the regular $80.

 

??? 37,500 miles equates to 59,200 kilometers, 30,000 kilometers are 18,642 miles

 

lol! good eye! its 60,000km/37,500miles/36 months/12 parsecs...

 

So I just changed my spark plugs, spark plug wires, and ignition coils, I used NGK spark plugs and spark plug wires and I used OEM coils after I swapped the old ones for the new ones my check engine light came on. Has anyone else had this problem or know what it might be?

 

You need to get the check engine light read.

Could be related or could be a coincidence.

I'm guessing you have a JDM model, is there a different coil pack for those vehicles?

 

What damage could be done to the engine if 4 leading spark plugs were installed (instead of 2x leading and 2x trailing) over a 2-3 yrs?

Another concern is that leading spark plug reach is longer (21mm) than the trailing (19mm), could the electorde/metal flint be sitting longer into the rotar, that metal pieces could have broken into the chamber casuing damage to the engine?

The trailing spark plugs heat range is 9 and the leading heat range is 7.Would the leading spark plugs installed in where the trailing spark plugs supposed to be, withstand the temperature and what would happen?

And what damage could be done if the ignition coils failed? Could the ignition coils failed becuase of the incorrect spark plugs installed (4 leading ones installed)?

If anyone has come across this issue, your expertise and experience would be much appreciated!!!!

 

Generally, the only problem with installing 4 leading or 4 trailing is that you won't get as much power or efficiency. The plugs are well recessed anyway, so no worries about the tip hitting an apex seal. The reduced efficiency could lead to earlier misfires, earlier plug failure, which then leads to cat failure, which leads to engine damage and vehicle fires.

Ignition coil failure is well documented. Asking "if anyone has come across this" is like asking if anyone else knows what happens when you forget to put gas in the car. The new owner's thread has a whole section dedicated to what happens when they fail, and how frequently you should change them. Please read that.

 

Thank you for your help RIWWP!!

Can having 4 leading plugs lead to earlier ignition coil failure? And can it cause loss of compression?

I have spend days reading up on all the threads and they have been helpful. I couldn't find a thread that is particularly to do with problems that can occur with having 4 leading plugs long term, and also can it lead to ignition coil failure or anything else / any other damage it can cause to my vehicle. ie. exhaust/emission system?

 

Specifically, no 4 leading or 4 trailing won't cause harm.

However, you are getting a more inefficient combustion if you do that, and you will need to change your plugs much sooner than you would if you had proper 2 leading 2 trailing.

Failure to change the plugs when needed is when the problems will start showing up. These would be the same problems as failing to change plugs when proper even on correctly located plugs. These problems will generally be fouling of the plugs, and coil failure, which will lead to cat failure, which will lead to O2 sensor failure, engine damage, and possibly car fires.

If you have 4 leading plugs at the moment, just change them to correct. If you are contemplating putting in 4 leading, just buy 2 trailing and do it right.