I got a scanner and plugged it up to the car and got a P0420 code (catalytic converter).
Could this be my problem and do I need to change the oxygen sensors too?
There is no service soon engine light and i am not burning oil.The car runs fine it just stumbles or you may call it miss fire when I throttle slightly over 1,000 rpm and slightly at idle, otherwise it runs fine.If I throttle from take off straight to 1,300 rpm all is ok.
Just to let you know I bought the car 4weeks ago from someone with the head gasket blown, they sold it to me as is.I did the work step by step with the tools specified.The cylinder head was reconditioned by a well known place called Dover cylynder heads in Atlanta Georgia.
When I got the car going a lot of antifreeze was still in the exhaust so I had to run it for a long time.
I installed NGK laser Platinum Iridium as recomended.
I will replace the cat by friday.
My friend owns the scanner so I will have to drop by his house again tomorrow>
Just to let you know that I pulled up consumerGuide automotive and their study shows this as a trouble spot for this car.
The article states-ENGINE STALLING:a problem with the ignition coils causes stumbling during light throttle cruise or stalling at idle,requiring installation of a resistor between the coils and spark plugs.(2002)What resistor are they talking about?
I am only having the stumbling during light throttle not the stalling at Idle.
I will scan it tomorrow checking the air and fuel mixture.
Yes I had a shop that specialize in nissan with a new machine relearn the idle and it is idling at about 700 -750rpm in park.
I took back the aftermarket coils because I got the same problem with them as the old ones.Are you saying what I was thinking in the first place ,is to go get the OEM from the dealer?The coils on it are the originals and they did get overheated when the previous owner blew the head gasket.
So them lets sum it up ,the new dealer coils are now improved with the resistor to correct this problem.
I saw a lot of blog about this same problem on the internet.
Before I buy any thing more I will get the coils checked then go from there.
I will get back to you tomorrow after I have the coils checked and then replaced.
I will let you know the outcome the we can close.
I finally got the nissan oem ignition coil and the problem is gone.