Help i have a 97 chevy blazer and it is really me off i have changed the injectors after i changed the injectors it started to run rough it didnt do it before the new injectors we hooked up a car md and it read that bank 3 was misfiring and i changed that spark plug and it is still running the same. it runs rough in park and kinda jumps up and it acts like it does nt have all the power it suppose to have any suggestions> ??????? also someone said it may be the o2 sensors and also may be the pcv valve? any ideas please help i cant afford labor costs!!!!!