2005 g35 sedan Well I hope I didn't make a BIG$ blunder:
I decided to change my spark plugs yesterday, was a few hours in between a BBQ and enjoying the cool weather. I went from ngk's iridium #4469 to bosch platinum +4, #4431.
I pull apart the booth from the ignition coil to see what it looks like and thought I put it back the way it was or at least hope so Now the car misses and shows that multi misfire shakes bad, I decided to drive it and see if it will go away Now the catalytic converter is RED hot. after about 6 miles of drive.

Is the check engine light on? Check your work and make sure all the boots are tightly seated on the plugs. Use a bit of dielectric grease on the tips.

+4 plugs are really gimmick plugs and the multi-prong setup does more harm than good. Going from NGK iridiums to Bosch +4 is a step backwards IMHO

agreed, I would stick with NGK, I have heard a few stories of Nissan engines getting upset with other brand plugs.

The check engine light was flashing when I drove the car approximately 6 miles. I picked up 6 NGK iridium plugs and 2 coil pack will replace tomorrow. I am still confused why the catalytic converter got so red hot last night.

I'm not absolutely sure, but aren't red hot cats a tall tale sign of too much fuel in the exhaust? It's possible your Bosch spark plugs may not be putting off a good enough spark to burn up the fuel in the cylinder.

be sure to gap your plugs accordingly as well

Wow............. The cats are red because the car is running rich and the cats are meant to burn the unburnt fuel. Stick to ngk never i mean never run bosch unless its on a American car even then they suck !

don't try to gap an iridium plug!!
they come pre set and if you try to adjust them you are likely to snap the electrode.

FLashing SES is usually a misfire...and a very bad one.

I wont blame the plugs here, instead, i'd suggest you check your COP's carefully.

P0300 is the code for multiple cylinder misfire. So basically something you did is causing all cylinders to misfire badly.

Change back to NGK plugs (really great plug no need to change) and make sure all your COP's are seated all the way.

The red hot cats are a result of the misfire. Fix the miss, and that should go away

Thanks guys Back to NGK iridium and also change 2 coil on plugs and the baby sounds like my baby was b4 I went and tinkered with it
Now I need to replace all the cable ties that I cut off the wire harness to get to the plugs and also the little plastic plugs that hold down the air ducts (sends air to the air filter) went to Auto zone and Advance Auto neither 1 have them, they seems generic, hopefully not a dealer item.
Thanks again.

I believe Lowe's and Home Depot carry those plastic clips. I swear I've seen a link for them on the forums before. You can also find the clips on Ebay.

what is COP? coil pack?

Coil On Plug.

Basically means you have individual coil packs mounted direclty on top of each spark plug.

http://www.ebay.com/itm/221016192246...#ht_1235wt_952
These are generic made in china but it's all you'll ever need. They are a little more prone to breaking upon removal but still way cheaper than buying them from nissan.

He isn't talking about these fastener. He was instead referring to the plastic zip ties they use to secure the wire harness.

They are your generic zip ties that come with most new assembly required items you buy from stores.