Serviced My Car, Now Feels Sluggish And More Rich.

[Shakiel]

When u pulled the plugs out you should have just checked the gap instead of believing they were gapped to 11!! Maybe check what they are if you still have them, and I would gap the newby plugs you got down to .8

Just might make the difference you are looking for. Also what year is your GTR? How many km's? These things are also what you have to consider when choosing what oil to use. But I think, since its very easy to do, is check the gap of your original plugs, then you know for sure whats going on there. I just dont think Edge 10/60 would make that much of a sluggish feeling.

I've seen an RB30/26 Automatic R33 Skyline being safe tuned making just over 240 rwkw, and then I got told to pull out the plugs gap them down to .8 and the next run it made 260 rwkw!!

[__PhaseShiftDown]

I checked the gap before I installed them.. even though I bought them with the -11 in the end.

Car is running on stock boost, 94 model with about 75k on the clock, at least thats what the speedo says.

I think -11 is ok to use, since my car is not missing or anything. I checked one of the old plugs when I pulled it out, and it was gapped 11 as well.

[Shakiel]

Maybe give the lower gapping a shot before forking out for new oil. Since you are on stockish boost try .9 see if theres any difference Where abouts are u located?