In general, Premium gas has more cleaning additives than Regular gas. Possibly, putting in the Premium gas resulting in cleaning whatever component was limiting your RPM to 2000 and helped you get to 4500. But, you should be able to get up to 6000+ if you floor it while in the lower gears - even with an automatic. I'm guessing that your EGR valve is crudded up, and slowly getting better when running Premium gas. Just a guess, though.

 

Well I tried to rev it up to 6k but retards timing when reaches 4k, it does make sense that it probably did clean up the system, then now the EGR code comes up and knock sensor which I think I already had before. Knock sensor is reducing my performance and somtimes when I drive the rpm stays at 1.5k for a little bit as if somthing Is clogged which leads to me a clogged EGR. And knock sensor I hear as if somthing metal is cracked and hearing a little "buzz" noise.

 

If your using 93 now and have a clogged egr and knocker sensor code. Your wasting the benefits you get when using 93. because your maxima is not breathing or responding how it should. Until you change those parts I suggest using regular gas. Change those parts asap man!

 

Well regardless I have the codes, I refuse to go back to regular gas cause of how crappy it felt, I had positive things come from using 93 octane. I am getting the EGR cleaned and knock sensor replaced very soon, probably when I get my paycheck on monday or tuesday.

The car runs great besides sometimes when I get stuck at 1.5k RPM for a little and the little buzz sound I hear.

 

I hear you. I can only imagine how crappy its running now with the knock sensor code. If you plan on keep your 4th gen for a while I'd go brand new everything skip cleaning egr brand new is only 60 bucks and you no its clean. Then use 93. You'll take off like a rocket.

 

only got 133k on my ride, no reason to get rid of it anytime soon

I bought those 15$ knock sensors on ebay, and have it with me and mechanics are telling me a buncha boolshet about how it wont work and stuff cause of how cheap it is

#1 I told them is "look these knock sensors for these cars have been used for over 20 years now for the same model/make, massive production of these parts, thats why its so cheap.

#2 "I have done plenty of research that people on the forums used cheap knock sensors off ebay and say they work just fine" They just not may last as long as OEM but a brand new cheap knock sensor is better than the one that is probably MELTED or Cracked that is sitting there!

#3 then he was like "oh"

 

Knock sensor can be a pita to change small hands do the trick though. Going the eBay route is cheap I know. Depending if your doing the work your self. That knock sensor should be able to get you by until you get an official nissan one. I've owned 3 4th gens and in all my experience these cars hate engine aftermarket parts.

 

From what I have heard, the cheap ebay knock sensors have lasted people 2+ years atleast.

 

classified section oem Nissan knock sensor 45 bucks.