Hey guys I really need some help with this one as I cant seem to find the problem. It all started Saturday morning when I changed my spark plugs, I bought the ngk iridium plugs and put everything back together. I leave for work and the car is misfiring like crazy, the next morning I take everything apart and put it back together still runs terribly. So, I take everything apart and put the old plugs in and still runs terribly. I figured maybe I should just go with the platinum plugs, so I buy the platinum plugs and put them in the car still runs terribly. Now I break a coil pack bolt so a coil is just loosely in there I lodged something I. Between it and the bracket just to see how it’ll run and keep it down and it still runs terribly. So I’m completely loss and very discouraged at the point, I cleaned my connections, I checked spark plug gaps, I torqued everything down to spec, what am I missing? Should I try cleaning the MAF next? The problem is the car was running fine before just bad gas mileage and was in need of new plugs and instead of doing what it needed now the car is a piece, any help would be immensely appreciated.

 

Also the coils look in good shape no bubbles and I’m going to buy a new valve cover since the bolt is stuck I tried to extract it but it failed

 

Did you do one plug at a time? Like remove one plug and coil then replace plug and go to the next one? If not it's possible you had the wires crossed. I always do one at a time to prevent wires getting crossed.

 

I'm guessing you mixed up the coil pack wires.

 

I don’t believe so does anyone have a picture of the correct way to do it?

 

Why keep banging your head against a wall?
As others have suggested you most likely crossed the coil packs.
Call AAA
Have them give you the free tow to your nearest dealer
Pay the one hour diagnostic fee and let the dealer fix your problem.
Lesson learned! You should have taken photos and marked the coil packs prior to doing the job
Happy New Year

 

It's a pretty common mistake that people make mixing up the coil pack wires, and the end result is bad misfire. Usually it's cylinder 4 and 6 that get swapped accidentally.

Check the FSM section EC - Engine Controls around pages 667 - 670 for the schematic so you can verify the wire color on the harnesses. I think grey is cylinder 4 and grey with red stripe is cylinder 6.

https://www.nicoclub.com/archives/in...e-manuals.html

Color codes are under GI - General Information on page 16, 17, 18 around the "how to use this manual" section.

 

I appreciate it, I’m going to check it out tomorrow at some point hopefully and see if that’s what’s wrong but if I do remember correctly everything is plugged in as it should be and I did not cross wires I did the first time but I fixed it.

 

only problem with that is that I’m in college, I don’t quite have the funds to have the dealership deal with it. It’s very frustrating that I go to do a basic tuneup put everything back together and the car runs like a piece. If me not taking it to the stealer ship is such an issue maybe you should just send me the money and I’ll do as you say

 

Everything looks to be in order so what do you suppose I do now?

 

Pull all the plugs and inspect them for damage, same with the coil packs. Use the FSM to verify harness wire colors when you plug everything back in.

Also pay particular attention to any of the pins in the harness being bent, it's easy to F up the pins.

 

Same with the harness for the MAF sensor since it's removed for spark plug change.

 

Never try to fix anything that isn't broke
When is the last time you filled your gas tank and drove three hundred miles, filled up again and checked your MPG by dividing the gallons to fill up into the miles traveled? (24 to 26 MPG is common)
You will never experience good MPG in any Infiniti if all you do is make short trips in stop and go driving.

Follow the troubleshooting steps in the FSM or hit the bank of mom and dad to lend you the money and let a dealer fix it for you.
If you used any non OEM parts remove them including non OEM plugs

 

I appreciate it my friend, I’m getting a new valve cover on Tuesday and will replace that and do everything else while I’m at it.

 

I know you checked the gap but are all plugs tight? Also did you disconnect something and forgot to reconnect? My 2 cents, you have a coil pack either damaged, not seated correctly or crossed. This thread may be of help guy dwapped plugs and had problems afterwards.

https://g35driver.com/forums/g35-cou...ncluded-2.html


I also second the motion not to touch anything unless it's broken or obviously about to go. I'm on the original plugs/coils going 17 years but only 65,000km. I've inquired about changing them 2 years now and the dealer sends me away lol, 'you are too early, the car will let you know when it wants new plugs'..