Nissan Repair: engine ping, frontier 2, reg cab

Question
I have a 2001 Frontier 2.4L 4cyl 5 speed manual reg. cab. 105,000 miles. I use this truck daily to commute to work, all highway miles, I notice when I get off the highway  to get home , on acceleration I hear a slight ping (pre-ignition) I use regular gas, Sunoco, I've tried the plus grade and different brands, same results. Shoul I use a cold spark plug?

Answer
Check the timing and make sure that you have a good tuneup.  Also, what is the temperature of the engine as a thermostat that is letting the engine too hot can contribute to pinging.  You did say it pings on super unleaded so I would guess the two things that can cause this are the temperature and timing that is too far advanced.