i have a question, my car seems to idle between 1100-1500 at night, not during the day but only at night. i dont drive any diffently at night and day, but it only idles at night, no CEL, and the car runs fine. its been doing this for a couple of week, what do u guys believe is causing proplem?? please help

also my setup it b16 head w GSR cams, C1 block w/ JDM ITR pistons, and chipped p28, its in a 93 civic, if that helps, thanks

 

Try the stock ECU see if that changes anything. You will get much more help in Tech.