I have a 99 mustang GT with a 2001 GT motor in it. I took the car off registration this winter because in CT we get bad winters. I started the car twice I week while it was in storage. I recently got it registered and when I try to give the car full acceleration it cuts out and hesitates. I took it to someone to look at and they told me to change my fuel filter and clean the MAF. Also the check engine light came on and the code read a bad O2 sensor in bank one cylinder one. I relpaced the fuel filter, bad O2 sensor and cleaned the MAF. The car is still hesitating. I think my next thing to do is change the spark plugs and check the coil packs. Maybe clogged injectors? I was wondering if anyone has any similar problems. Any advice would be appreciated.