Hello and First Off Thank You for allowing me to join.

I have a 2002 Maxima all stock with 110000 miles.

A couple of weeks ago it started almost stalling with no pattern at all. I am pretty michanical. It is throwing no codes. I just did a full tune up with new OEM plugs and checked everything out. Cleaned the MAF Sensor and everything. Fired it back up and ran it around the block and it was running like a new one then bam it started stalling out again but never totally dies. The only lights the flicker when this happens is the battery and brake light. If I pull the positive cable while running it keeps going. At idle it is charging at 13.7. When I go to rev it up it will sometimes go up above 17 volts and stall out again.

This thing is driving me nuts. Is it possible the alternator is over charging and when it does causes it to go to idle mode. This problem comes and goes and no matter air on lights on everything it does not change. It will then run like a new one for a mile or so then do it again.

Please help. I am thinking it is the alternator, what does everyone here think.

 

Usually when the brake and battery lights are on its a faulty alty as I like to say. Some of them just flat out die and when you unplug the positive it should turn off. But since it stays on the regulator could've gone bad. If you have a lifetime warranty I would just replace the entire alternator.

 

As far as I know it is the original one.

 

The alternator is bad, the voltage should always be in the range of 14.1 to 14.7 volts. However, I doubt that this is causing the low idle.

If the engine rpm goes too low, like maybe 300 - 400 rpm, the alternator cannot charge and the battery & brake lights will come on. This part is normal.

Since the intake manifold has to be removed in order to replace spark plugs, most likely there is a vacuum leak. Go back and check all the hose connections again. If you have some starting fluid, spray it around the intake manifold area, the manifold gasket and all the hoses. Do this while the engine is idling and if there is a leak, the starting fluid will make the engine rev.

 

I will change the alternator for sure then. I hope that is what it is. It is running great when it runs if that makes sense.

 

How old is your battery? It sure looks like an alternator problem but a bad battery can also act weird. I would try to check both.

 

^^THIS^^
Go back and check all the vacuum lines to make sure they're not split or cracking at the clamps. They may look good but have a split or crack you can't see. Also make sure you didn't split the intake boot.

Starting fluid works well for finding a leak but brake parts cleaner or your MAF cleaner will work fine too. Spray the lines and where the manifold comes together.

 

If you end up having to replace the alternator here is my tutorial on how to do it. It's a pretty easy job it just takes time and patience.