My 86 na makes a strange popping sound in idle. it isnt consistent, sometimes it doesnt make the sound sometimes it does. It doesnt seem to happen until the car is warm then it makes it.

I replaced the mass air valve and the o2 sensor recently. and it still does it.

 

You are going to have to be waaaay more specific or try to post a video of the noise in action.

 

A little bit of afterburn can be normal if the car is old or in poor tune. Have you replaced the plugs and wires lately? Do you have all your emissions equipment in tact?

 

new plugs, new wires.

It doesnt happen consistently, i do believe it could be in poor tune given an amature knowledge of rotaries. or a vacuum leak(maybe)... it doesnt happen until the engine is warm and even then it sometimes goes away then comes back.

It has a new cat as well.

 

Vid you can hear it in the first 5 seconds

http://www.youtube.com/watch?v=D1wIU...e=channel_page