Blown MAFS...again

[BP2K2Max]

i was just seeing cuz my friend had a jeep and the fuel return became disconnected from offroading so any fuel sent back through the lines wasn't being brought back it was just being spilled. it drastically lowered his gas mileage.

[joeB]

Originally Posted by skids929

The tank is 18 or 18.5 gallons I believe. I fill up with Super and get about 210-220 miles to a full tank. So thats about 11-13 mpg city or highway, it doesn't matter. It is unbearable, I can literally watch the guage go down. . But there are NO lights on saying there is something wrong with the car.

I thought that our 98 was bad on gas. Something else must be
wrong with your car. I asked our service guy today about the 02 sensors in Maximas, and he said that even if they go bad you
shouldnt notice much of a gas mileage differece.

[skids929]

I appreciate you asking your service guy....But be sure to tell him, he has no idea what he is talking about if he thinks a bad o2 sensor won't effect gas mileage. Honestly, I can't believe some of the crap these people at Nissan come up with, it is like they receive no training. The o2 sensor has a BIG hand in deciding how lean or rich the car will run, so it WILL effect gass mileage, as will the MAFS.

[joeB]

I dont know, Ive never had it happen just once in 96, and it was
replaced right away under warranty.

[EPVQ30]

i've been getting an average of 300 miles per tank since i bought the car new.
it's not the best, but i hasn't gotten worse since i put an intake on.
skids why don't you bring the car to the dealer, maybe they can diagnose the problem for you.

[BP2K2Max]

it sucks that there is no CEL on. that would make it 10x easier. it could be a lot of things. fuel filter. fuel pressure regulator, fuel pump, 02 sensors, your catalytic convertor could be clogged. piston rings, injectors, spark plugs(although you say the car runs fine) coil packs, throttle body, MAFS, your timing could be off.

[QuickMaxima]

Originally Posted by BP2K2Max

i was bringing my friend back to his house and was coming around a turn when all of a sudden the car started bucking until it went down to 2400 rpm, and the shit won't idle lower than 1000 rpm and won't rev higher than 2400. this is the second damn time. last time i was wide open on the gas trying to show my intake off to a friend, this time i was just cruising barely over 3K. what a load of bullshit

The 2002 MAFS is a known weak spot on the Maxima. Get the updated part number and replace the sucker. This is a well documented problem with several hundred dealer replacements from Maxima.org alone...

[skids929]

I have replaced the fuel filter, air filter, PCV Valve, Fuel Regulator, plugs and the rear O2 sensor up to this point. The fuel pump is fine. Have not checked the catalytic, doubt it is clogged at 29,000 miles, and I would probably be losing power if it were faulty, but anything is possible.

I went to the dealer today and they said there is nothing wrong with it. That is after I ran a tank of gas and got 14.4 MPG. I went 228 miles on 15.8 gallons of fuel. I will try another tank from another gas station and see what happens. Maybe I got a bad tank of gas with too many additives (doubtful) or maybe the really cold weather (negative temps) we had last two weeks has a greater effect on the car than I thought. My 03 Accord V6 had no noticable problems with gas mileage in the cold though so I doubt that is it either. Who knows, it looks like I might be chasing this for a while. Thanks for all the suggestions, keep em coming!

[BP2K2Max]

Originally Posted by QuickMaxima

The 2002 MAFS is a known weak spot on the Maxima. Get the updated part number and replace the sucker. This is a well documented problem with several hundred dealer replacements from Maxima.org alone...

yeah, i've been there already. that's why i put the "...again" in the thread title. it ended up just being a fluke thing cuz the car's been running just fine ever since the day after the incident. i'm thinking since it was snowing i sucked some moisture in my intake and it froze on the sensor. that or the filter itself got wet and froze and air couldn't pass through. right now i have an 03 mafs that nissan used to replace my 02 under warranty, but thank you anyway for the help. and this is no longer my thread. skids came through and hijacked it right out from under me.

and skids man, have you tried running a fuel system treatment like STP? maybe you just have some build up.

[eclipse5764]

Originally Posted by BP2K2Max

i was bringing my friend back to his house and was coming around a turn when all of a sudden the car started bucking until it went down to 2400 rpm, and the shit won't idle lower than 1000 rpm and won't rev higher than 2400. this is the second damn time. last time i was wide open on the gas trying to show my intake off to a friend, this time i was just cruising barely over 3K. what a load of bullshit

Yo man my buddy has a 02max and has the stillen intake on it and his MAFS went twice two. the same exact thing happend to him with the friggen car going into safe mode. its because water is gettin into it due to having the intake. water is gettin up into the MAFS now becasuse the stock air box isnt there to block the water.......... either make a shield to block the water or put the stock intake on. it isnt even that much horse loss so dont worry......... my buddy put his stock on back on and now has no probs with the damn MAFS........

JUStin

[thrasher]

Dude, this thread is almost 1 and a half years old, not really relevant at all. Old threads = don't dig up from the grave

[BP2K2Max]

1) this thread's old, but it is still an unresolved issue and it's still my biggest gripe about the 5.5 gen maxima's.
2)can't say for sure about your friend, but in my case it wasn't because of water, it was because the aftermarket air filter had too much oil on it. switch to an Apexi filter, which doesn't require oil, and you'll be all set. don't use foam filters.

[99redmaxSE]

Originally Posted by BP2K2Max

i was bringing my friend back to his house and was coming around a turn when all of a sudden the car started bucking until it went down to 2400 rpm, and the shit won't idle lower than 1000 rpm and won't rev higher than 2400. this is the second damn time. last time i was wide open on the gas trying to show my intake off to a friend, this time i was just cruising barely over 3K. what a load of bullshit

my car goes through the same shit. as long as i drive the car good it wont mess up at all as long as i just drive it hard once in awhile. but once i start driving it hard more often then it starts to choke like you described...and this never happened before i had my intake on it

[BP2K2Max]

I had issues with my 95 maxima when i put an intake on. i got a CEL, the idle was lumpy at times, and there was occasional power loss. you know what actually fixed the problem? that Tornado Fuel saver thing you put in your intake piping. i can't explain why it worked, but all the issues i was having went away and never came back.

[EPVQ30]

Originally Posted by BP2K2Max

I had issues with my 95 maxima when i put an intake on. i got a CEL, the idle was lumpy at times, and there was occasional power loss. you know what actually fixed the problem? that Tornado Fuel saver thing you put in your intake piping. i can't explain why it worked, but all the issues i was having went away and never came back.

lol thats a riot pao cause everyone claims that tornado thingamajiggy is the biggest hoax.