Need new MAF

potsdamcartel · Dec 29th, 2007, 04:11 PM

I just got back from the dealership and they told me that I need a new MAF sensor (@$550).

But before I commit, I have a few questions;

Wouldn't a bad MAF sensor cause the Check-Engine Light to turn on? Mine didn't, and never has since I bought the SUV new in 04.

Would a bad/dirty MAF sensor cause knocking sounds from the engine?
These sounds could be detonation pings, but I am not sure.

The reason I sent it in was because I was getting fluctuating revolutions whenever I hit the accelerator. It felt as if the engine was struggling, more-so than usual going uphill. I was also experiencing what felt like light bucking when I was on the highway going at speed. Finally, occasionally, I would hear what sounded like knocking coming from the engine. The sound would appear, then disappear after abit.

At first I thought it was Rod Knock, but I do change and check the oil regularly. Inaddition, the dealer didn't mention anything like that (however, judging by the way they behaved, it really shakes my confidence on how thorough they examined my engine). Also, isn't Rod Knock suppose to persist, and not disappear? The sound wasn't present when I visited the dealer.

In anycase, I plan on cleaning the MAF sensor myself before I hand over $550. But, if cleaning does not work, can I replace the sensor myself? I read somewhere that the sensor must be replaced by the dealer, because the ECU must be re-calibrated to the new MAF sensor, but I am not 100% certain on the legitimacy of that statement.
Can I replace the sensor myself?

The vehicle in question is a 2004 Nissan Pathfinder, with alittle over 30k miles on it (heh, conveniently out of the warranty that would cover the MAF sensor...)

Thank you for your help.

**88pathoffroad** · Dec 29th, 2007, 09:50 PM

Those things do die all the time on 01-04's. I'd go to AutoZone or any other auto parts store that scans error codes free and see if that code comes up for them as well.

It takes no special tools or computer work to install a new one. Plug and play. Take a look here: a new one for your Pathfinder will cost you over $300, but a Maxima MAF fits right on with no problems for around $100.

Cheap 01+ MAF sensor problem fix! - Nissan Pathfinder Off-Road Association

potsdamcartel · Jan 10th, 2008, 06:42 PM

I hooked up a scanner from Autozone and got no codes.

My check-engine light has never come on in all my years of owning the truck.
Afterward, I asked an independent mechanic about my symptoms, and told him what Nissan recommended. He told me that if it Was the MAF sensor, the check-engine light would have come on.

But, as I stated; my check-engine light has never come on.
Nissan's diagnosis, and how the Service Department behaved, makes me very suspicious about the thoroughness of the examination.

I made an appointment with them at exactly 8AM and dropped off my truck.
They kept it the full day, overnight, and told me it was the MAF sensor the next morning.
What makes me suspect about their thoroughness was the fact that the road the dealership is located-on, is a major avenue in town.
I literally drove by it, in my cousin's car, exactly 6 times (to a destination, and back) throughout the day. And each time I drove by, I saw that my truck was in the exact same spot I had left it in. Infact, at around 7PM, I grabbed my spare Fob and actually went back to my truck to pick up a Blockbuster movie I had left underneath the seat.
I saw that nothing had changed, the interior was exactly the way I left it; no paper floor mats, and even the gloves I left on the driver seat hadn't been moved.

Ha, when I went to pick it up, I asked the Service Rep why the check-engine light hadn't gone off.
While shrugging her shoulders, she replied,

"I don't know why it didn't go on." "Thats why it took so long to find the problem."

As I stated; their behavior has me very suspect on how thoroughly they actually examined my engine.

Has anyone else experienced a similar problem?
What could the problem be besides the MAF?
With 30K miles; I have replaced the fuel filter, cleaned the MAF, and plan on having my cats and spark plugs/coils checked tomorrow.

If it isn't the cats or coils, I'll order that Maxima MAF, which by the way, thank you very much for that link 88path. 'save me atleast $400.

**88pathoffroad** · Jan 12th, 2008, 04:39 PM

I read a post by one guy recently who actually TOOK APART the MAF sensor. It's a weakly-made part with poor connections that are easily breakable. He soldered the joints inside back together and hasn't had a problem since.

I would recommend that if you're going to take the trouble to do 6 fly-bys to see what they're doing, turn the wheels when you park it so you can tell if it's been moved or not, and TAKE PICTURES. Then go back with proof and let the shit fly.

Call the BBB. Call Nissan NA. Do your worst.

potsdamcartel · Jan 15th, 2008, 05:43 PM

I just ordered a replacement MAF, however; I found another symptom today:

I am burning oil, I found no puddles or leaks.
And I am not sure how much I burned, but the last oil change was ~500 miles ago.

**88pathoffroad** · Jan 16th, 2008, 07:35 PM

The PCV valve lets oil be sucked back into the intake and burns it. The fix for that is a replacement valve cover with a baffle inside. The dealership SHOULD know what that's all about, but...

One guy I heard from said he bought a cheap clear plastic fuel filter and just plain plumbed that into the PCV hose between the valve cover and intake, it catches a lot of the blowby without hindering the PCV system's function.