Check Engine Soon light came on
 

Hi all,
Yesterday I was driving my 1997 Maxima and the "Check Engine Soon" light came on. Also while driving I noticed that while pressing the gas pedal the car does not accelerate as normal. It takes a second or two to accelerate and when it does, it kind of jump or does a quick accelerate. It does not do a smooth accelerate. Any ideas? I do not know if the acceleration and Check Engine Soon light are related but they both happened the same time.

Pull the code. It'll tell you what's wrong.

I took it to AutoZone and they said that the Knock Sensor shows up. They did not tell me what code.

Usually the knock sensor is a ghost code, meaning that it will pop up almost anytime there is another problem with your car.

When the knock sensor is actually bad the car will perform like crap, and that sounds like what your car is doing so it might actually be the knock sensor.

Head over to ebay and buy the cheapest knock sensor you can find and get a harness for it too.
Should run you under $60 shipped for both.
Search for the writeup.
I think Phomor has a YouTube video on it as well.

Good luck!

Go back ... Geezus.

Go back, have them pull the code but this time ask what is. The actual code that is.

Geezus ... Those ****ing guys.

Just ask them for the goddam code.

We can all sit here and type opinions and experience all day but your car's gonna tell you what's wrong.

Get the goddam code ...

Something like 2 years ago my check engine light was on. Stopped by autozone and the experts there said I had code P0308. I asked them to point out cylinder # 8 to me and they couldn't.

Why would you expect them to know which cylinder is #8? Every manufacturer numbers them differently.

I was hoping that they could make the task of finding cylinder # 8 easier. Silly me.

:funny: went right over your head....

Because Maximas don't have 8 cylinders? He didn't say that was the car he took there. If that was the joke, he needs to tell it better.

That was no joke. It actually happened. And it was on my 97 Maxima.

Truth is stranger than fiction.

OK, I went back and got the code. There are 2 codes showed up
1) P0100 (Man, absolute pressure/board or maf\Air Mass flow
2) P0325 (Knock Sensor condition)

I had the guy reset the Check Engine Light and after driving about 25 miles, it came back on.

The knock sensor is often a piggyback code. Start with the MAF. Clean the MAF first, if that doesn't work, replace it.

I did a search on the forum for "Mass Air Flow Sensor" and I got a lot of hits but none is showing me where it is located and instructions how to replace. Can someone post a link -thanks

It's next to the air filter...

http://easyautodiagnostics.com/nissa...es/image_1.jpg

By itself
http://i27.photobucket.com/albums/c1...F1995-1999.jpg

Ignore the arrow in this pic. The MAF is next to the cone air filter
http://www.motorvate.ca/auto/maxima/...ima_engine.jpg

Oops, didn't refresh.

I did the 2 voltage test to check if the sensor is bad and it seems it is bad.
The test I performed is with the key in the on position, I check the voltage from Pin 3 on the sensor harness to ground and I got 12.7V.
I then check the voltage from the white wire terminal to ground and I got 1.5V. I am told it this voltage is between 1V and 1.7V then the sensor is bad. So my question is does anyone has a Sensor for sale? Please contact me.

Check out the 4th gen classified section, either the part for sale individually or someone parting out their car.

Or contact Maxima_Joe, the used parts king.

OK, I've contacted Maxima_Joe and bought the MAF from him and installed it. I don't get the rough jerky acceleration as before but couple of things now. I drove the car for about 80 miles and the "Check Engine Soon" light did not come off as yet. Do I need to reset the Check Engine light or will it come off by itself. I did not change the Knock Sensor yet as I am planning to do it this weekend.
The second thing is the car is not accelerating fast enough. Although the acceleration is smooth it is taking extra time to get up to a normal speed. I have to press the gas all the way and wait for it to get up to a good speed. Thanks for any help.

The CEL is supposed to go away on it's own, but more times than not it doesn't. Just clear it yourself either with a scan tool or the ol' screwdriver and ECU method.

The lack of power is due to the bad knock sensor. You should confirm that the KS code has indeed returned by doing a scan. A bad KS by itself doesn't trigger the CEL, but if you scan for it, it will be there.

OK, I took the car to AutoZone and they reset the light. I also replaced the Knock Sensor and the car still does not accelerate proper. I do not get the jerky acceleration anymore but if I have to change lanes I have to make sure I have lots of room between the incoming car. Any idea what can cause the acceleration to be slow? I changed the air filter also and added a bottle of Injector Cleaner last week to the gas. Thanks for everyone help.

When the KS goes bad you lose like maybe 10% power. It's not that bad. maybe 1mpg loss in mileage too. Barely noticeable. My car had a bad KS for about 8 months before I replaced. Everything else was good.

Replace your primary O2 sensors and maybe your catalytic converter is bad also. Do the O2s first though.

Also, how is the maintenance on your car? Spark plugs? Platinums last 60K miles. If you don't know the last time, I would suggest you change them. You can use NGK copper plugs which won't last as long, but they are cheap. Usually the assumption is that all regular maintenance items have been taken care of. How well maintained is you car?

Fuel filter? That should be changed every 30K miles to keep the car's performance optimal.

Knock sensor is a piggy back for the MAF like said up there ^^ change/ clean maf and i bet ur codes will both go away. If not change the Ks with an ebay one there are good write ups on the forum and some vids on youtube. If u have fed spec like i do on my 99 it is a pretty simple job took me 10 minuets

If it's the knock sensor then here is a video I made. It will give you a better understanding of where it is and how to replace it yourself. $ave money!! Take it easy. - Ozz

Stop wasting your time going to autozone, check the codes yourself. There's a write up in this forum as well as youtube videos showing how.