Spark plugs on a 99 6cyl Sport

JfirEfightErP · 05-16-2009, 08:08 PM

hey, I'm going to change the spark plugs on my 99TJ this week and was wondering which plugs were the best for that year, 6cyl. I searched and from what I gathered the plug needs to be double platinum, I also heard that they changed during the middle of the production of TJ's, not sure how true this is. So if anyone knows the best brand and number for my jeep that'd be awesome, sorry for being redundant. Also, does anyone have a write up for this out there? I',m a younger guy and have never needed to change plugs and have never tried it, seems pretty straightforward. So if anyone has a writeup or any suggestions I'd appreciate it, thanks guys.

kaybone · 05-16-2009, 08:15 PM

I absolutely HATE Platinum plugs. Sitck with the tried and true Champion Truck plugs part #4412. I've been running them for 6 years now and engine runs smooth and no problems with them.

Let the flaming begin on my platinum plug opinion!

Here's yer write-ups:

http://www.stu-offroad.com/engine/tune/spark-1.htm

http://www.4x4xplor.com/sparkplug.html

Pillswoj · 05-17-2009, 10:06 AM

On your 99 you still have a distributer so there is no need for double plats. The 4412's that kaybone suggests are good if you don't mind changing plugs every 25 - 30K. Just as good are the Autolite AP985 single plat that will last upwards of 90k.

**Stu Olson** · 05-17-2009, 10:17 AM

Champion Truck 4412 plugs

**Jerry Bransford** · 05-17-2009, 11:26 AM

I used to run Champion 4412 plugs in my '97 TJ 4.0L engine but I switched to Autolite AP985 platinum plugs because they last 3X as long and the engine runs exactly the same as it did on the 4412 plugs. The first time I pulled my AP985 plugs at 60K+ miles to see how they were doing, they still looked almost brand-new with no visible erosion at the gap so I reinstalled them. 90-100K miles can be expected out of a high quality platinum plug like the AP985 which is a very good choice for 97 to 99 model year 4.0L engines. 2000 and newer distributorless 4.0L engines have different spark plug requirements.

**TheBoogieman** · 05-17-2009, 11:47 AM

Autolite AP985'S for me.

sealion2288 · 05-17-2009, 02:57 PM

Quote:

Originally Posted by Jerry Bransford

I used to run Champion 4412 plugs in my '97 TJ 4.0L engine but I switched to Autolite AP985 platinum plugs because they last 3X as long and the engine runs exactly the same as it did on the 4412 plugs. The first time I pulled my AP985 plugs at 60K+ miles to see how they were doing, they still looked almost brand-new with no visible erosion at the gap so I reinstalled them. 90-100K miles can be expected out of a high quality platinum plug like the AP985 which is a very good choice for 97 to 99 model year 4.0L engines. 2000 and newer distributorless 4.0L engines have different spark plug requirements.

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