I got this code in my 98 teg ls. The codes been of and on for about a year now. Just lately tho I've started to get a pretty hard miss on take offs and a slight miss in low (500-1500) rpms in just about every gear. I replaced the solenoid back by the tank along with the valve and the solenoid on top of the canister. I also pressure checked all the vacuum line and they tested good. So if you guys could give me anymore ideas id appreciate it thanks.

 

seems like you did everything necessary for that code...P1457 is a failure in one of the evap system solenoid valves. there are 2 culprits, the vent control valve & the 2 way bypass valve. they crap out due to corrosion/contamination from water seeping into the valves.

if you replaced thoser then i would have the ecu cleared...don't just pull the battery cable but take it someone like autozone to actually completely erase the ecu