I have a 91 Mustang Conv LX 5.0 Automatic. I went out and it wouldn't start one morning, which had me scratching my head. It has 105,000 and I bought it before winter so I didn't get to drive it much last year. After a while I went out to read the codes to see what might be wrong. It popped a 41 and a 91 fault code. I changed the fuel filter since I didn't know if it had ever been done before . It still pops the same 41, 91. I then did the Cylinder imbalance test and it gave me #7 fuel injector as out of balance. Sry, the codes show fuel injectors out of balance. Does this mean that #7 needs to be replaced? Any help would be great!