need help
 

i have a 2000 dakota slt, ext cab, 3.9, auto, no mods. put in a new jasper 3.9 motor kit in it. everything new except for the intake and everything on it. occasionally it will get a bad skip in it with a spark knock, then almost shut off completely, if the ac is on it will knock off. always starts back with no problem, then it may not skip for a month, or in 20 minutes. it sometimes will go for a month and not do it. it shows a misfire in the odd cylinders only. also the a/c compressor will shut off at times and not come back on for 30 minutes, then sometimes it works perfect. any help would be appreciated.

bolts or brackets if not tight can make the computer think is a knock. check for something loose.