Friend has a 97 maxima with a p0306 code. 168K miles on the odo. The car runs great when the engine is cold. When it warms up, the idle fluctuates up and down, up and down and will finally stall. I suspect a vacuum leak. There is no gas smell or white exhaust. I sprayed starter fluid in the engine bay areas but it has no effect on the idle speed. I am stumped for now. Suggestions?

 

Misfire on cyilinder # 6. Suspect coil or plug. Relocate both of them to another cyl. If the problem moved to the new cyl, either the plug or coil is at fault.

If his idle speed was set kinda low in the past, a missing cylinder could cause a stall.

 

We put in a new spark plug in cylinder 6 and changed around the coil pack and there is no change. I suspect it is an injector problem or a vacuum leak. The car does not stumble when accelerating so I am not sure that it is an injector. The idle just fluctuates up and down in park and drive and soon stalls.

 

I have never heard of a vacuum leak causing a mis-fire code (P030x), so I would persue the fuel injector route.

 

I respect your opinions Dennis because you have helped me before. But listed in the causes of an OBD P0306 is a vacuum leak. I am going to pursue the fuel injector route since I cannot seem to find a vacuum leak, although there are vacuum leak symptoms. The car ran fine until his daughter borrowed it. She drove it the end of the street and turned around and came back because it was stalling when she stopped. I was standing there when it happened.

 

PH, please do a Google search of P0306..

You will see that it applies to a miss in cylinder #6 in any automoble. Not a vaccuum leak.

Where did you read that P0306 is a vaccuum leak?
I' like to see your source of information.

since you swapped out the coil and plug on #6, the likely remaining cause is indeed the fuel injector.
How recently has the injector in # 6 been serviced or replaced?

Other possible cause might be a bit of oxidation in the wire or contacts to the coil or injector on # 6.
In that case, the plug, coil, and injector could be brand new, but the code would still appear.

 

I am not here to argue. I did a Google search and it lists a vacuum leak as a possible cause for OBD P0306. However, I am pursuing the injector as the cause.

 

A vaccuum leak can cause missing in one cylinder.
Could be a bad intake manifold gasket, or a leaking injector o ring.

That said, our cars have known issues with injectors. You might try trading #6 with another injector. If the problem remains, its a vaccuum leak, perhaps a burned valve.

 

[QUOTE=JvG;9170962]A vaccuum leak can cause missing in one cylinder.
Could be a bad intake manifold gasket, or a leaking injector o ring.

That said, our cars have known issues with injectors. You might try trading #6 with another injector. If the problem remains, its a vaccuum leak, perhaps a burned valve.[

keep in mind, P0301-306 are all cylinders. All can have the same issues,. Includine vaccuum issues. P0306 is no different than any other P0301-to P305 codes

 

Fixed the injector problem. Thanks all.

 

PH, since someone will look at your post in the future, please tell us how you ultimately solved your problem.

Thanks.

 

We replaced the suspected injector with a cleaned up and tested JY injector.