Recently my 2003 honda civic ex has been almost dying when I slow down or idle and just yesterday my check engine light came on with the code p1259 vtec system malfunction. What could this be and how much will it cost?

. Ensure the oil is the proper viscosity Honda recommends. I would only use full-synthetic engine oil in a VTEC.

. Check/replace the VTEC Pressure Sensor. Check connection and wiring first.