Engine misfire P0300/P0301/P0302/P0303/P0304

So I was recently driving my jimny it's worth noting I've swapped the bottom end of my m13a for an m16a so it's somewhat modified it is all running on factory m13a ECU and electronics and since the modification I've covered around 2000miles with no issue whatsoever how ever when I was driving I all of a sudden lost power while under load the car had power around 1/3 throttle but would cut anything above I limped about 1 mile to where I could safely pull over and pulled my obd 2 out and read the codes P0300/P0301/P0302/P0303/P0304 by this point the codes were no longer active and the car had returned back to normal operation I've checked my coils and done a quick inspection of my wiring loom and there was nothing obvious coil packs were mostly in good shape there was a slight tear in the cylinder 1 rubber gromit on the coil pack but other than that nothing that would suggest any arcing has occured from the coil packs anybody have any ideas what happened and where I should be looking next ? My only thoughts are cam/crank sensor over heated perhaps ? 

Assuming you are back to safety have you checked the plugs, they can tell you a lot. Though giving a code for each cylinder does suggest a bad connector or something equally sensor related. Another alternative is a blocked catalytic converter that often manifests as power loss.