Sometimes sputtered while driving. Hit gas hard and run fine. Then sometimes wont start. Backfire through intake. Sputter run after ignition is off. Sound to me like timing. Then get in one day cranks fine. Then again wont crank. Changed crank sensor run fine again for a while. Have had problem for a year now it wont start at all. Also noticed when running sometimes fuel pump is louder than normal, but not always.