does anyone know anything about what i think is ping at 1800-2400 rpm when my programer is on "tow" mode but not in stock mode? the only mod i have is a K&N cai wich i here can cause a problem but i have been running the two together for over tow years and it just started 1 1/2 months ago.

 

spark nock possibly

 

low octane gas mine does it too if i get cheap gas from small stations