2011 dodge 6.7

[adchome]

i just installed extreme power puck. have 2011 dodge 4x4 manual trans. 373 gears, 3500 series single rear wheel. 500 miles on truck. the fuel mileage was 13.5 on highway and it has now jumped to 20.3 miles per gallon. this has been for the last 150 miles.
after installing the puck. my check engine light came on and electronic throtle control light. but after 30 miles both went out and have not come on again. does the computer reset itself after adding a puck? or do i need to look into the problem?
thanks steve

[mikel]

Id see if it has any codes stored.