Tune-up spark plug questions

[TransamNick]

I have 70,000kms (like 45,000 miles I think but I'm too lazy to check exactly) and I have no idea if the previous owner (drove it until 60,000Kms) has ever done a tune-up.

My questions are:
1) what spark plugs originally came with a 99 T/A (platinum?)
2) what was their lifespan?
3) and when should I be looking to do a tune-up?

Thanks for the help!!

[Mr. Luos]

1. ACDelco's
2. GM claimed a lot. I would replace them at 40K miles.
3. I would probably do the basic tune-up stuff every 2 years if I was stock.


NGK TR55 plugs, gapped at .054" for a stock LS1.

[TransamNick]

Thanks for the info

[Fred H.]

My 2002 WS6 came with Denso platinum plugs (PTJ16R15) in it.

I am not so hot on the NGK TR55 plugs, mainly because I would rather use an Iridium plug in this car, or at least a platinum. The spark plugs are such a pain to change in this vehicle, that I think you are wiser putting in a plug that will last a long time, like an iridium.

The NGK TR55IX (iridium) would be a better choice in my opinion.

Some folks like to use the TR55 standard plug because they feel it makes more HP, but I would argue that the gains are minimal, and the TR55IX will still have sharp electrodes and be firing like new after 20K miles, where the standard plug will start to degrade in performance after only 7K-10K miles or less. So over the long haul, the iridiums will actually give you more power. Initially the standard plugs may give you a very slight gain, but they will go downhill fast, so you better plan on changing them OFTEN.

[Mr. Luos]

I don't use the TR55's for power.
I use them for accurate and consistant spark.

I have the plug changes down to about 45 minutes, so once a year isn't a big deal for me.

The TR55IX will last longer, but perform roughly the same.
To me...they aren't worth the 4x price.

TR55IX - Roughly 4 times as much, but last 3 times as long.

[Fred H.]

I don't use the TR55's for power.
TR55IX - Roughly 4 times as much, but last 3 times as long.

In my case it isn't about the money, its about the hassle factor and time of changing them. For every one spark plug change I do, you will be doing 3 or 4 (or more). Iridium plugs can easily go 75K miles without wear on the electrodes or the gap opening up significantly.

If you can do a spark plug change in 45 minutes, more power to you. It takes me at LEAST a couple hours, and the back right plug alone can take me over 30 minutes.

[Mr. Luos]

I understand the hassle factor 100%.

I have done it so many times...just gotten it down.

[trev0006]

I change plugs every 30k

[1 TRANS AM]

I have put 16,000 miles on my car. It now has 50,000. I have changed my plugs 3 times. I love a fresh plug change!