Hi guys! Just bought a 99 gt (80k miles). On the ride home, I noticed it had a miss fire under load and the CEL is on. I changed out the coil packs for new Granatelli's and installed all new o2 sensors. After taking the car for a test drive, I noticed the CEL came back on. The codes its throwing area for all 4 of my o2 sensors being bad and an evap leak? .......Anybody ever had a problem like this?