use ngk spark plugs
http://www.carstereohelp.com/stereoremovalNisPup.htm
Check the radio/Acc fuse...
Go to www.installdr.com .
engine noise coming thru the radio is caused by a bad ground somewhere so instead of chasing that you go to a car stereo shop and buy a noise filter that hooks up to the ground wire coming off the radio.
A bad noise suppression condenser. Usually attached to the alternator.
Go to your local autoparts store and buy an adapter.
Radio suppressors for the alternator etc., and suppressed spark plug leads.
This may help. On older vehicles, unless one used "resister" type spark plugs, one would get a lot of engine noise through the radio.
Nissan pulsar radio pin 4362 Nissan pulsar radio pin 4362
radio lol
You can find one of these diagrams online. An image search can help you out though it is really complicated and may need the assistance of a professional.
Believe it or Not You have to Change your Spark Plug and Distributor Wires, to Noise suppressor type wires and probably put in a noise suppressor filter in the Hot wire that runs the Stereo. I know it sound different but this works.