I used octane booster as I thought it worked, after my research I just use 93 octane gas. The copper plugs I had ran the same as my platinums so I doubt they are any issue but I'll switch back to the tr55s and see if there's any difference

 

i would agree if you changed the plugs and got no change its unlikely its the plugs. copper will run good for a short time at the least. maybe look at spark to see if you have a bad wire, other than that have the injectors cleaned and flow tested at a injector shop. not that costly and if never been done its probly time. check egr, catyletic converter, muffler, coil wire, coil, evap, well lol, all i can think of.