2001 Nissan Pathfinder SE 4x4 5spd 3.5l question about MAF sensor...

[whatchugot12]

Hey all! Got a bit of hesitation with my truck upon start up and was wondering if anyone has any ideas on what I should or could do? I have done all the main stuff within the past 6-9 months. NGK Platinum plugs, fuel filter, air filter, new muffler, and fresh oil changes as needed. My tires are 265/70 r16 General AT2'S so I understand that my mileage for gas might be decreased by a little bit but since the new muffler 2 weeks ago it's even worse. I'm getting about 14.5-15.75 mpgs and thought with the new muffler I'd be possibly increasing my mpgs. Anyhow, I saw on the 96-04 R50 Facebook page that someone had changed their MAF sensor and that it now runs like new. Keep in mind that my Pathfinder has been pretty well kept and maintained so I'm leaning towards purchasing a new one (MAF sensor) just to see what happens. I'm no mechanic though and would appreciate any information or advice for doing this swap. Picture of my truck below. Thanks in advance!

 

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[Mbrianc]

Get the Maxima maf. Some of the pathfinders have security torx screws, mine just had regular torx screws. Real quick change, just don't drop it. I hear they are somewhat sensitive to shock.

 

The Maxima maf was cheap enough that I just changed mine when I did plugs and coils. You'll have to clear the self learning and relearn idle air volume afterwards though.

 

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Edited March 13, 2017 by Mbrianc

[DarekG]

I'm a newb so this might be a dumb question but how does a bad muffler affect fuel mileage?

 

The reason ask is because the end bits of my exhaust fell off, including the muffler, and I've been too lazy to come up with a fix.

[Qctech]

I'm a newb so this might be a dumb question but how does a bad muffler affect fuel mileage?

 

The reason ask is because the end bits of my exhaust fell off, including the muffler, and I've been too lazy to come up with a fix.

 

Your exhaust is designed by the manufacturer to give the proper pressure feedback to the engine to maintain certain compression/fuel mileage. It is a complex system and explaining how exactly it works would be out of the scope of this answer. What you have to know is that an improper exhaust system will affect your milleage negatively and in extreme cases even your engine, because it may not be create the correct backpressure and cause problems in you pistons. And no , it is not a dumb question. Proper exhaust design and performance is an engineering task. The only fix on your case would be to buy a new compatible muffler and have it installed.

Edited March 28, 2017 by Qctech

[Citron]

It's not as complicated as all that. Pretty much any muffler would work. Heck, you could put a glass pack on and not have issues. Sound like crap on a V6 though. Usually, people get worse mileage with new performance mufflers because they like the sound so they put their foot into it more.

 

Much more important is cats and O2 sensors. Bad or improper cats can effect the O2 sensor which will change your air fuel ratio.

 

Muffler simply muffles the sound.

[Qctech]

The MAF can be cleaned with electrical contact cleaner spray before wasting money on a new one. What you want to check first is all your vaccum lines for leaks and then remove the inlet to the throttle body and see how dirty yout TB is. Sometimes, carefully cleaning your TB will do away with the hesitation you are talking about.

[adamzan]

Do you have a way to see the live data? I have a bluetooth obd2 connector, hooked up to my old android phone running torque pro. I used this on my Xterra to troubleshoot bad o2 sensors that weren't throwing codes, but causing it to run weird/have poor gas mileage.