help please

[Tech5]

I have codes galore. great.

I have a 99 Civic Si. Thought I had a bent valve, but it was carbon build up...and had the valve replaced last night. Check engine light was on and these were the codes pulled:

P0118 Engine Coolant Temperature Circuit High Input.
P1259 VTEC System malfunction.
P0171 System is too lean.
P0301 Cylinder #1 Misfire or Random Misfire.
P0303 Cylinder #3 Misfire or Random Misfire.
P0304 Cylinder #4 Misfire or Random Misfire.
P0300 Random Misfire.

"what is causing these codes?"

Did you install new plugs an wires? If not do that
also double check the timing with misfire an running lean sounds like the timing is off that also will make the vtec not work too, check make sure all the connectors are hooked to the right location..Make sure you didnt un do the injector harness ..this are just some ideas you have my number later ,josh

[chip P.]

tech 5...whats up guy its been a minute. still throwin out good info i see..x2 about good connectors

Did you install new plugs an wires? If not do that
also double check the timing with misfire an running lean sounds like the timing is off that also will make the vtec not work too, check make sure all the connectors are hooked to the right location..Make sure you didnt un do the injector harness ..this are just some ideas you have my number later ,josh