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Andrew 08-20-2009 07:32 PM

1999 WJ Spark Plugs
What are the best spark plugs for a 1999 Grand Cherokee Laredo?

IV6 4.0L

Pulstar Spark Plugs?


Chaoul1 08-20-2009 11:13 PM

Re: 1999 WJ Spark Plugs
IMO I think you should just go with the factory spark plugs. Because they are the correct ones for it.

Dylans3960ccs 08-21-2009 06:27 PM

Re: 1999 WJ Spark Plugs
E3 dimond fire spark plugs.

mjl2610 08-22-2009 10:09 AM

Re: 1999 WJ Spark Plugs
The straight 6 motor spark plugs are easy to change. You might as well just go with factory ones and change them whenever you need to. However, it might be interesting to find out how single platinum champion plugs (rc12pec5) will run in it also.

Dylans3960ccs 08-22-2009 11:33 AM

Re: 1999 WJ Spark Plugs
I'm going to get some new spark plugs right now I'll tell you what I buy and if it's really worth getting claimed better ones.

mjl2610 08-22-2009 01:04 PM

Re: 1999 WJ Spark Plugs
Dont go overboard with the super fancy ones. Its more than likely not worth it. The regular copper champions were 2.15 for my 4.7L. So i went with the closest spec Champion platinum power single platinum that is supposed to be fully compatible and everything for about 85 cents more. Almost 10k miles later no pre ignition, smoother idle and no problems to report. I figured by staying with champion it would be my safest bet all around.

Dylans3960ccs 08-22-2009 06:54 PM

Re: 1999 WJ Spark Plugs
Ok I bought those E3 spark plugs and everything about it is better, it idles better, it's quiter and from what I can tell has more power.

---------- Post added at 07:54 PM ---------- Previous post was at 07:53 PM ----------

I give them an A!

Chaoul1 08-22-2009 07:46 PM

Re: 1999 WJ Spark Plugs
I called my dealership and they said that the Mopar spark plugs are $6 each.....

Dylans3960ccs 08-22-2009 08:09 PM

Re: 1999 WJ Spark Plugs
do you have a pic of this IV6?

lol j/k

Andrew 08-23-2009 09:05 AM

Re: 1999 WJ Spark Plugs
So champion is the OEM for 99 WJ I6?

I will go with the best champion spark plugs.

I know how to change them, very easy.

Thanks guys!

Dylans3960ccs 08-23-2009 11:47 AM

Re: 1999 WJ Spark Plugs
does anyone know the torquing specs for the spark plugs and coil-overs?

mon_21 08-23-2009 03:15 PM

Re: 1999 WJ Spark Plugs

Originally Posted by Dylans3960ccs (Post 50742)
does anyone know the torquing specs for the spark plugs and coil-overs?


Special care should be taken when installing spark plugs into cylinder head spark plug wells. Be sure plugs do not drop into plug wells as ground straps may be bent resulting in a change in plug gap, or electrodes can be damaged.
Always tighten spark plugs to specified torque. Over tightening can cause distortion resulting in a change in spark plug gap or a cracked porcelain insulator.
1. Verify that each plug is correctly gapped to 0.035. Apply a small amount of anti-sieze to the plug threads. Start spark plug into cylinder head by hand to avoid cross threading. It's best to do this by using just the socket extension bar and socket. Carefully turn slowly while keeping the extension bar as vertical as possible. You should be able to screw the plug all the way in by hand until it "seats" snugly.
2. Tighten spark plugs to 26-30 ft. lbs. (35-41 Nm) torque. If you do not have a torque wrench install plugs snug and then turn 1/4 turn.
3. Connect engine harness connector to coil by snapping into position. Move slide tab towards engine for a positive lock.
4. Position ignition coil rubber boots to all spark plugs. Push down on coil assembly until bolt bases have contacted cylinder head.
5. Install 4 coil mounting bolts. Loosely tighten 4 bolts just enough to allow bolt bases to contact cylinder head. Do a final tightening of each bolt in steps down to 250 in. lbs. (29 Nm) torque. Do not apply full torque to any bolt first.
6. Connect negative battery cable to battery.

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