I just found out that my new-to-me '96 GXE has the NGK platinums in the 6 heat range. Almost all of my driving is short trips around town, so it seems pretty clear to me that I should switch down to the 5 heat range (it gets hot in the summer around here, so I don't think I should go to the 4's). My question is: what kind of problems will I have running a plug that's too cold? I've perused the appropriate stickies, and other than the potential for fouling, which I'm not experiencing, there don't seem to be any major symptoms mentioned. Will I experience any performance improvement by switching? I would think my fuel economy might improve slightly since the plug will heat up earlier in my short drives.

 

PFR5G-11 is the factory equipment.

PFR4G-11 is the Nissan approved replacement if you want a hotter heat range plug, suitable for
- frequent engine starts
- low ambient temperatures

PFR6G-11 is the Nissan approved replacement if you want a colder heat range plug, suitable for
- extended highway driving
- frequent high engine revolutions

I suggest you stay with the 5G unless you have a specific reason for changing to a hotter or colder plug. This might include major engine mods such as Nitrous.

 

I personally noticed a slight decrease in power when I had the 6 plugs in as did others, but other users reported no loss. It seems random to me.

 

Either that, or your car was in a bad mood that day. Moody Moody car.

 

http://forums.maxima.org/showthread....threadid=45742

So Daniel doesn't have to repeat himself.

 

This link took me to the 4th-gen maintenance items sticky which I had already mentioned that I had read before posting. It still doesn't answer my question, though: what kind of problems/issues might arise from using a colder plug than recommended? I already acknowledged that I'm running a colder plug than I should be for my driving pattern (lots of short trips), I just want to know how urgent it is for me to rectify the situation.

A followup question that I have is: does the Nissan factory put in a 6 heat range plug if it knows a particular vehicle is destined for use in a hot climate? I had been under the impression that my plugs are original to the car, which is why I was surprised to not see the 5 heat range plug in there. I know that 4 & 6 heat range plugs are acceptable alternatives to the 5, but I had thought that they always have the 5 from the factory and that it's up to the owner to switch if he wants.