Idle trouble..Code 10 and 14!!

Put new timing belt and water pump in. 1991 Civic Lx. 1.6 lt. Have code 10 and 14. Idle is surging from 800 to 1500 rpm. Runs great, timing is good. Plenty of power. Tried new idle valve..nothing. Current is 5 volts, so I think that is o.k When I reset the ECU the fault is back even before starting car? ECU out? Does this control Idle valve? Read about Vac leak or tps, not sure if thats the problem. Runs great down the road until you come down a hill and take foot of gas then does alot of surging. Fine again when push on gas. I would appreciate some help guys, im starting to pull my hair out. Thanks Jags

10. check your intake air temperature sensor. check ohms cool and at normal operating temps? what does it read? also, check for continuity from sensor wires to ecu.

14. idle air control valve. make sure you are using a known good one. no tears, clogs, or rips in the screen. check wiring from iacv to ecu. make sure all coolant lines are good. all lines are where they are suppose to be?