2007 Impala LT 3.5 with 304,000 miles. I finally fixed the EVAP check engine light. It has been on for 200,000 miles. I had replaced the vent solenoid, purge canister, 2 gas caps, fuel tank pressure sensor and checked all the hoses and wires I could. I made a hole above the fuel pump in the trunk and looked at the fuel tank pressure sensor wiring. The green signal wire coming from the ECU was broken about 6 inches back from the connector. I spliced it back back together and it has been off for 3 weeks. It still shifts and drives just like it did when new. Hallelujah!