New here and hoping for help.I have a 99 silverado that i changed the motor in do to main and cam bearing ware.Put new/used motor in now this one has a misfire i cant get rid of.I changed pluges, wires, coil, injectors, o2 sensors, and egr and its still there does anyone have any other sugestions please help

 

are you getting po300? Sometimes a cracked intake will cause that code. try doing a compression check on the cylinder that is missing. I had a 5.3 that had a dead miss that caused all sorts of funny codes. Turned out to be a broke valve spring on the intake side

 

yes did comp check on all cyl n they were all at 152 to 155