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That is my first guess too. I suppose it is possible one was on the way out, and me moving them caused a mis fire. Cyl #1 was a little difficult to get out, may have bent it slightly. Still no CEL, The missing is kind of subtle, until you get into the load situation at low RPM, then it is obvious. I suppose I'm going to have to take it to a dealer or a shop that can diagnose which cylinder is missing, and then narrowing it down from there. It is just aggravating; the car was running like a top. I thought I would do some scheduled maintenance, and this happens. BTW did the 12 hour battery off ECU reset, no joy, still missing. I did wipe the dirt off the inside of the throttle body with a little carb cleaner, but did not go past the butterfly. Also knocked the big bugs off the K&N filter that has been installed for over 80k miles. Still looking for any help
Thanks to everyone who contributed to this thread...I just did the plugs in my 2004 coupe and the install went perfect. I'm the original owner and I have 115k miles original plugs too(I know shame on me for not doing it sooner)
Only main issues which I already suspected were the valve covers. My drivers side and pass side is leaking pretty bad as cylinder 2,6 and 5 all had oil pooling in chamber. My heart pretty much dropped when I pulled cylinder 6's coil as it was dripping with oil. It was half full of oil can't beleive that coil lasted all this time. I knew for sure that the moment I was done I would be misfiring but surprisingly it started up good and I drive around my neighborhood for a couple miles and it was fine.
Now the question lies...do I buy new valve covers and coilpacksthat together or just get 3 new coilpacks that had oil on em?
These are the original spark plugs from my 2006 w/ 101K miles. Took longer than expected and luckily didn't see any oil leaking in tubes. However I do need to replace the VC gaskets. Can't decide if I should replace the VC or just the gaskets.
Thanks for the pics and step by step instructions. Took about an hour but I have a bad back and had to take numerous breaks. Only issue I had was I dropped a screw down into the back of the engine compartment. Never did find it. So now I have to go to the Infiniti dealership to get a replacement screw (was the screw that secured the wires).
My G just turned 100,000. Not bad for a 10 year old car.
I know this is an old thread but just did my plugs and worked awesome!
wow mine has 115k miles, time to replace the plugs!
many thanks to writers of this thread.
one big question though.
which of these plugs are the best?
G-Power LFR5AGP
5018
.044
Laser Platinum PLFR5A-11 * #
6240
.044
Iridium IX LFR5AIX-11
4469
.044
The G-Powers are just plain old sparkplugs, nothing fancy about them. They'll perform adequately but need replacing in a very short timespan. You will probably need to inspect and re-gap them yearly.
The Laser Platinums are the factory installed sparkplugs. They're designed to last forever (and but forever I mean 100k miles/160k kms). You will probably sell the car before you ever have to replace these again. They will perform better than the G-Powers as well.
The Iridium IX are the high performance spark plugs. They're going to give you the most intense, most complete burn and are heavily resistant to fouling and spark blow-out due to Forced Induction. They're going to last you a lot longer than a G-Power plug but not as long as a Laser Platinum. If you want maximum performance and you're OK with changing your spark plugs every 3-4 years they're the ones to go with. If you just want to drive your car and never have think about your spark plugs, get the Laser Platinums instead.
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First, half of the credit for this DIY goes to QuadCam. He posted the instructions for this, which I used to do my own plug change. I just took the pictures, and am making this a separate post. So, THANKS QuadCam!
I installed LFR5AIX-11 plugs. They are the same heat range as stock. QuadCam installed the LFR6AIX-11 plugs. The install is the same procedure
First, the tools you will need:
6 NGK Iridium IX Sparkplugs
3/8" Rachet
3/8" long extension (at least ten inches)
10mm socket
10mm open-end wrench
16mm "deep" socket (or "sparkplug socket")
Magnetic pick up tool
3-prong grabber (optional, you'll need it if you don't have a "sparkplug socket")
Pliers
Torque Wrench
Most people would have these tools in their garage. The long extension is a must. The magnetic and pronged "pickup tools" make this much easier.
PROCEDURE:
1) DISCONNECT THE NEGATIVE BATTERY TERMINAL! Loosen one 10mm bolt (RED arrow), this is the only step where you will use the open-end wrench.
2) Remove the engine cover. It is 2 10mm nuts and 2 10mm bolts (RED arrows)
3) Remove the intake tube. This should require the removal of (2) 10mm bolts (RED arrows) and loosening 3 hose clamps, one on each end of the intake tube and a third clamp on the breather tube (BLUE arrows). Use pliers to loosen this last clamp, then pull the rubber tube away from the intake pipe. Removal of the second 10mm bolt located at the air box will facilitate easier reinstallation of the intake tube later.
4) Let's start on the driver's side first.
5) To gain better access to the coils, you'll need to remove 3 10mm bolts which hold down an electrical harness just above the coils. All the bolts are easy to get to. You may have to push a couple hoses out of the way to get the back bolt though. Be careful not to drop the bolts!!! The magnetic pick-up tool can be very helpful here!
Front:
Middle:
Rear:
6) After you have removed the bolts for the electrical harness, Disconnect the plugs going to the individual coils. There are 3 plugs to undo. They are snug, but they come off fairly easily with just your fingers. Simply depress the flat lever section, and pull. Do not pull by the wires. Pull only on the gray plastic connector. If necessary, use a flat-blade screwdriver to help the connector come loose. Remember which plug goes to which coil. That is extremely important!!!! (They may be labeled).
Cylinder 2
Cylinder 4 & 6
7) Now you have good access to the coils! Use the 10mm socket to remove the bolt from the coil. Once you have removed the bolt, the coil will pull straight up out of the head. This should be very easy to pullout.
8) You should be able to see the sparkplug in the hole. It is pretty far down there.
9) Use the 16mm socket with the extension to remove the plug. If you aren't using a sparkplug socket, you'll need to use a 3-prong, spring loaded pick-up tool. This tool makes plucking the plug out the head very easy. I'm sure you can come up with some other sort of tool to do the job, but that is what I used.
10) Prepare your new sparkplug. These come pre-gapped! You do not need to gap them, and you will probably cause problems if you do. Coat LIGHTLY the 3-4 threads closest to the non-electrode end of the plug with a coating of Anti-Seize lubricant. A small tube or bottle can be purchased at any automotive store.
11) Replace the sparkplug with your new plug! Torque the plug to 20 FT-LBs! Make sure not to crossthread or overtorque the plugs! Aluminum heads are easy to strip out!
12) relplace the coil; torque its bolt to 95 IN-LBs and plug it back in to the harness.
13) Repeat steps 8-11 for cylinders 4 & 6!
14) Re-secure the wiring harness with its 3 10mm bolts, and the driver's side is complete.
15) You can also replace the intake tube at this time.
16) On to the passenger's side of the engine.
17) This side is slightly harder....only because some of the bolts are difficult to reach by hand.
18) I started by removing 2 10mm bolts which retain the wiring harness. I only removed the 2 bolts closest to the front and middle of the head. The rear bolt is not necessary to remove.
19) You will need to remove the rubber breather tune that runs from the valve cover to the intake manifold. Use the pliers to loosen the clamps; then, slide the tube off of the engine.
20) Now, you should be able to disconnect the electrical plugs from the coils. This is the same as on the driver's side.
21) The coil removal and plugs change is the same as described above. The only difference is that the back (toward firewall) coil bolt is difficult to get to with your fingers. Use the magnetic tool to remove and replace this bolt.
22) After repeating the procedure for all the cylinders, you should be done. Make sure to check that all the electrical connectors are snug and "clicked" tight.
23) Very important, you shouldn't have any extra bolts laying around!!!!
24) put the engine cover back on. Secure it with its 4 fasteners
25) reconnect the negative battery terminal.
26) YOU ARE DONE!!!!!
I think I remembered all the steps. This took me about an hour, going at a leisurely pace. Additionally, I was figuring it out as I went. With some motivation, you could probably do it in 1/2 an hour.
Have fun,
Andrew
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Man thank you very much for detailed explaining this job! I have 2008 Infinity G35 Jorney sedan and that is going to be my first thing to do-replace those spark plugs.Hi five!
So I just changed my spark plugs. And to be absolutely honest, I'm not sure if these were ever changed in the life of the car with (190,000 KMs = 118,000 Miles). FYI - My car idled fine with no noticeable vibrations or noises. This was a preventative maintenance (but definitely a must and long overdue).
I changed the spark plugs from its OEM NGK Laser Platinum to NGK Iridium IX. These plugs come pre-gapped and ready to go. So far about 50KM with the new plugs and the car drives very nice. One problem I had was the car initially had lower than normal idle RPM when left idle for about 15 seconds (which caused rough idle due to low RPM) but when I opened the hood to inspect one of the hose that goes into the intake pipe was undone. Once re-clamped the hose, idle RPM went back to normal and the problem never reappeared.
Unlike some that said they definitely felt the boost in power? I didn't feel any noticeable gains but I "feel like" it's running smoother and sounds quieter. This just might be true or it might just be a placebo effect. In any case I'm just happy the new Iridium plugs worked same spec as the Platinum plugs. I've heard some mixed review on that on this forum.
Here's what the OEM plugs looked like after I pulled them out. Notice the gasket leaks but overall not too crazy. The tubes were clean and the top part of the plugs were nice and dry. The plugs got dirtier as I handled them so take that into consideration. The second picture shows some massive wear on the plug tips! Almost nothing left... I'm so glad I changed them when I did. DON'T BE LIKE ME AND CHANGE THEM ON CORRECT INTERVALS!
Anyways, I hope this helps in some way and good luck!
03-04-2015, 03:56 PM
Awesome pictures and instraction!
