timothybailey35

i have a 1996 . chevy caprice ss and when you first start it. it runs fine to it hits closed loop then it will start to miss fire. will move around some then stick to number for cylinder mainly. engine was out he vehicle for about 6-7 months then reinstall to repair oil leaks. checked compression ok 150-160 on all cylinders, performed a running compression test seems to be normal. sent injector off and had cleaned and checked which came back ok. replaced opti spark, mass air flow sensor. all four o2 sensors, both converters, new plugs and checked for vacuum leaks none found. can use scanner to switch ecm into open loop mode and vehicle runs fine. can anyone help me with this issue.