Mechanic says Air Mass Meter. I need advice

5SpeedMax · 10-29-2009, 12:35 AM

My 96 Maxima SE 5 speed began accelerating poorly the other day. It feels like it has dead cylinder/cylinders because it runs roughly and loses power when it does this. Gas mileage is bad too. It is somewhat intermittent occurring during acceleration starting at about 1/4 throttle. It goes from smooth powerful acceleration to poor rough running and also does this while pulling a low rpm's from 2nd or 3rd gear while the motor is under load. Driving by just tipping the throttle it drives fine, its when I ask it to go that is the issue. One thing to mention, I've never had a check engine light come on. I hope I explained this clearly enough.
I took it to a mechanic and he said I need a new air mass meter. Yikes, these aren't cheap. I read in the the forum about coil packs causing this. What are these? Could this be a problem instead of the mass meter? Are they cheaper to replace? How many are there? Where do they go on the motor?
The car goes from hauling butt to just sounding like its hauling (through stillen air cleaner) but just dragging butt. I should mention I put a Stillen intake kit on it a few months ago but its run great up till the other day. Does anyone have an idea what my cars problem may be? Please help an old guy who still likes to floor it and cherp it off in second gear. I love my car but not so much at the moment. Help me love it again.
Thank in advance for the help
PS I'm new at this forum stuff so excuse me if I haven't learned all the etiquette yet. I'm trying

chillin014 · 10-29-2009, 07:56 AM

I would say unplug the MAF to diagnose it but it doesn't sound like you are having any problems with idling or stalling, right?

Coil packs are part of the ignition system that connect to your spark plugs. You have 1 per cylinder. 3 are easily accessible under the engine cover on the front of your motor and 3 are under the intake manifold in the back. You could buy a good use coil pack on this forum for pretty cheap or an auto parts site like Rockauto.com.

I try to buy one coil at a time and swap them out one by one since I'm tight on money, but note that the front and rear coils are not interchangeable.

I had a missfire caused by coils awhile back that would cause a very light stutter at a stop light and horrible loss of power only when I was giving it a lot of gas, like you are describing. Get yourself a maintenance manual.

mahanddeem · 10-29-2009, 08:28 AM

are your plugs NGK and OK ?

Andy2000max · 10-29-2009, 09:21 AM

My recommendation would be to search this site for links to the Owner's Manual and the Factory Service Manual (FSM). You can usually find them on-line for free. They provide a good education.

Don't listen to that mechanic. There is no way he can know it's the mass airflow (MAF) sensor if there is no code for it. He is trying to do guesswork and you will pay for it. There are many things you should try before paying a mechanic to do a potentially unnecessary repair.

njmaxseltd · 10-29-2009, 09:26 AM

Quote:

Originally Posted by 5SpeedMax

Does anyone have an idea what my cars problem may be?

Apparently your mechanic does.

Quote:

I took it to a mechanic and he said I need a new air mass meter

Why don't you just listen to him rather then asking us for a "guess"?

njmaxseltd · 10-29-2009, 09:29 AM

Quote:

Originally Posted by Andy2000max

Don't listen to that mechanic. There is no way he can know it's the mass airflow (MAF) sensor if there is no code for it.

If he has a scanner he can see the signal from the MAF in real time, easily spotting a problem or slow response from the sensor.

You don't always get a code, thats why scanners show you real time.
Trouble shooting 101....

**Nealoc187** · 10-29-2009, 09:39 AM

If it turns out to be the maf, you can buy them all day long used (and working) for $40-60 on here or on ebay. I just sold one the other day for $40 off my old maxima. Problem sounds like it could be coilpacks, which take the place of distributor and plug wires on our motors. One on top of each spark plug. You can buy sets of those all day long on here used for like $75. If you end up needing those I have two sets of good working coilpacks for sale from two previous maximas, if you want to buy them used. New I think they are like $100 a piece lol, no reason to pay that. new mass airflow sensor is something like $400, again no reason to pay for a brand new one when there are good used ones available in plenty.

5SpeedMax · 10-31-2009, 12:28 AM

Well as it turns out it wasn't the air mass meter at all. Yesterday I decided to find an independant garage that has all of the modern equipment for testing fuel injection equipment and the like they even had a chassis dyno. It wasn't going to be cheap but I didn't want to slap an air mass meter on the car based on a couple mechanics experiences and hunches.
They tested the car, the AMM is just fine. It had a bad knock sensor that was screwing up the engines timing. To make matters worse, some dummy put some bosch plugs in it about 80,000 ago. Some were loose in their holes or not screwed all the way in and most had their electrodes burning away.
Looks like I am going to have to start working on cars again at least for the simple stuff. I haven't worked on cars for 30 years always taking it to the garage.
Anyway, the car goes like a ball of fire again. It was a costly fix but not as much as it would have been had I installed an air mass meter like the first two mechanics I talked to said.
Now I'm a happier but lighter in the pockets guy but the spend and experience for me was worth it.