Having problems with my KA HELP!!!

[RB180sxChris]

Ok guys my check engine light is on....the codes are P0400 and P0440....I have a s14 it starts right up no problems what so ever...During the day is when I have the problem only when its hot out....when I drive at night no issues at all but anyways when I drive a good amount of miles and I come to a stop light for example id sit at the light my RPMs would dip a few times and as I'm going the car would start to sputter feels like either a fuel problem or bad plugs but I put in new NGKs....I cleaned the maf, there's a new fuel filter...the car still sputters when driven for a good amount of time...someone said to me timing ,the distributor is bad, get colder plugs.......anyone know off the top of your heads know what could be the problem??? Your help would be much appreciated

[Vernal]

p0400- EGR Flow Malfunction; could be sticking open when its hot. Check the vac hoses.
p0440- Evaporative Emission Control System Malfunction; possible evap/canister hoses, gas cap loose, purge valve

[dlucke17]

I had the same issue in my 96 when I left my freaking gas cap at the last store I filled up at. Check that first... Plus, if that is your issue you should be able to smell gas..

[RB180sxChris]

Thanks ill give it a try