Car Issue

To all my car people out there: 1998 Nissan Altima with 150,000. It has been well maintained and had many of the major repairs completed. There is still something wrong that annoys the heck out of me. When in "P"ark, the exhaust makes a pop, like there is too much or too little exhaust. It enough to be audible when I am in the front seat. The tach drops maybe 50-100 RPM when it pops. It happens maybe once every 30-60 seconds. Any ideas or quick fixes?

Carefully observe your ignition system at night and see if you can see any sparks jumping around the coil(s) distributor, wires, plugs…


Sounds like a possible misfire

Burnt valve?

Check engine light on?

Check engine light flashing?