My 98 civic is giving me a p1457. I replaced the gas cap with a facory cap, and I replaced the canister and two solinoids from a 98 civic at the local parts lot. had my a mechanic do a smoke test. There were no leaks datected.

I figure the problem has got to be a bad vaccum sensor or a shorted wite related to the sensor somewhere.
Does any one have the details on testing that vaccum sensor or any other suggestions to try.