Spark Plug Replacement Interval

[ACR Joe]

Any recommendations as to the effective life of factory spark plugs? My 99 has 12,500 miles and I thought it might be time to install a fresh set. Also, what's the best type spark plug to use?

 

[Brad Manhattan Beach]

Joe:

I am interested in getting the answer to this question. I would also like to know the interval for changing out the plug wires, and which are the best fo ra Gen 2 GTS?

Thanks for the feedback.

 

[BigsViper]

The Owners manual for my 2000 GTS says change plugs every 30,000 miles and wires at 60,000 miles. Maybe the gurus have other suggestions for heavy racing or other circumstances.

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It also says "check the underhood label for the proper type of spark plug" and "ignition cables should be replaced with the specially designed RFI cables available at your dealer".

"A luxury once sampled becomes a necessity"

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Don Bennett aka BigsViper

 

[BWoodbury]

This one of those areas where I just don't care what the manual says. In my garage all vehicles get new plugs every spring. 24 spark plugs is just not much money...

 

[Mike Brunton]

I changed out my plugs after running only 116mph trap speeds at the track.

All the right side plugs were detonating or running lean, and when I put the new plugs in - holy moly! - it was like a new car. I feel like I gained an easy 50hp from the swap. The car would run hard in 1st, but now it will break traction when I hit the torque peak in 2nd also. And I have compared on days with similar temperature and similar tire heat, so it's not a weather thing.

Looking to dyno the car soon, and can't wait until the track opens up again!

The recommendation I got (indirectly) from Dave Schotz was that the NGK FR5 plugs were the ones to use, since they run a bit cooler (extended less into the cylinders) and prevent a bit of the detonation you can get with the stockers. I'm going to change from the Champions I put in to the FR5's sometime before spring arrives.