After reading on the forums, it seems pretty clear that I should be putting a higher grade fuel in my 1999 Maxima tank. I've been using regular 87 gas cause people would tell me that's fine for my type of car. However, that doesn't seem to be the case.
I have about 1/4 tank left of regular fuel. Should I wait until I'm close to empty to add the higher quality gas? Or can I just put it in now?

 

Put it in, 100% zero effects from mixing gas. Go with 91 if you have it nearby, 93 only if the gas stations near you dont offer 91.

 

Start using a higher octane anytime. Go 91 or 93 which ever you choose.

 

If you didn't already have a few threads, I would have said this is a troll thread.

Switching octane at any point is fine, just don't mix brands of gas. Once you start with say Mobil gas, you have to stay with that brand of gas for the rest of the car's life. Or, if you want to switch, you have to get every last drop out of the gas tank, then fill up the tank with vinegar and water (perfect 50/50 is best), then run the car for 15 minutes. This is like cleaning your coffee machine at home. Then, siphon out the water and vinegar and your gas tank will be cleansed and ready for a different brand of gas.





























j/k

 

Step away from the vehicle, put the key down.
You're going to have to sea foam the entire car, just cover it completely then drive around the block. Your neighbors are going to think you're crazy, but trust me they'll understand

After that process is completed, you may put what ever fuel you wish to use in the tank.

 

so if ur saying to stick to the same brand for the rest of the car life, doesn't that make it a little too strict? cause that would mean u would have to go to only mobil gas stations...lets say ur on a roadtrip..low on gas.. no mobil gas station around but there is a gas station nearby.. but its not mobil.. then ya screwed..?

I just use 87 gasoline any gas station I go, and my family has done the same for many decades, so i dont see the effect really.. its just gas. just aslong as ur not putting diesel! haha

 

The O.P. asked a question that the others are having a lot of fun with.


You can put anything you want in the Max. The knock sensor will tell the computer to retard timing if it senses knock from 87 octane gas. The engine is designed for premium gas. If the timing is retarded both mileage and power will be less than if you use premium.


HOWEVER: If the knock sensor is defective the computer will retard the timing all the time as a default to save the engine. If the knock sensor is no good you will get the same mileage and power from 93 as on 87. That is why some members feel that it is a waste of money to put in premium gas.


I put 93 in my Max all the time. I had a bad knock sensor, but I did not know that. I replaced the knock sensor when it showed up as a ghost code that came up when I had a CEL checked out at an auto parts store. I had FAR more power and mileage improved when the new knock sensor was installed.

 

that's no excuse. Plan your trips around gas stations.
You see, I'm a Shell man.When I go on road trips I stop by the shell gas station and I stuff my trunk with multiple 5 gallon gas cans to ensure I'm never left stranded.

 

hmm that is smart, but sometimes u know life does those "bad days" or whatever ya say, or bad situations and have no choice but have to do it. no other way around. and im pretty positive everyone has those experiences.


And JvG how much more "power" are you talking? Personally I've tried 89 gasoline once, didnt really notice any difference. just a "tad" bit more power but barely. never tried 93, as the car tank in the car says to use regular gas.. which means unleaded 87 gasoline, not superplus(89) or premium(93). So I just find it better myself not to do things manufactures say that they do not recommend for gas or anything really. u never know what it could do overtime.

just my opinion.

 

^^^ is this guy for friggin real!?

 

I picked up 3 bottles of Sea Foam (buy 2 get 1 free at autozone). I used two bottles all together. The stuff smells nasty. I wiped it all over the car (windows, tires... everything). How long am I supposed to keep it on until I can put premium gas in the tank? It's completely dry now, but the surface of my car feels very rough like sandpaper. I hope I didn't damage the paint.
Anyway, as long as this resets the car to use premium gas, I'm fine with it.

 

Uh oh.

 

Probably wouldnt hurt to add the third bottle. Just make sure you let it soak up the sun itll actually add a few horsepower by the time youre done.

 

 

for shell thats my ****

 

I'd say upgrade if you're driving style is aggressive and your outdoor temps are getting hot.

I've downgraded on the Maxima and the car runs fine on 87. Been using it ever since these gas prices went thru the roof. I've changed my driving style as well to get the most out of my tank. I'm also using TC-W3 to condition the fuel. No problems and the engine runs smooth.