stumped, knock sensor, timing

[95yota]

any thought is greatly appreciated, o.k here goes i have a 95 1.8 i just bought for 200 to make a long story a little shorter i did a compression test and it needed a new head (bad valves)
anyway bought a head completely redone from a good rep. place. new timing belt, water pump,ngk plugs
10mm wires fresh gaskets, the whole 9 yards, heres the issue or issues when i got the car it had 4 codes
a igniter code, knock sensor code, and lean and a rich code so im assuming all this was due to the 25lbs of compression in #2 , the knock sensor had been replaced by the previous owner
as of now the car runs pretty good xceot on thing i still get a code 52 occasionally then goes away then comes back and so on ,as for the other codes i havent seen them pop back up , not sure if this is related
but when i drive it sometimes gives a hickup almost like it wants to die then runs fine for miles, then repeats , idles fine 750 rpm sounds good , i have looked at all connections numerous times, i dont think a knock sensor will give a hick up , im just thinking the hick up may trigger the knock sensor code due to it was already changed, i have checked timing and is good ignition is at 10bdc where it should be
any thoughts ?????