hi all. I know there is many threads on this subject. I am new here so any help is greatly appreciated. I have a 96 impala and have been chasing a random misfire code. At wot it runs like a champ but once it warms up idle sucks and it hesitates in low rpm. So far I have replaced all four o2 sensors optispark plugs, wires, egr valve , vacuum lines and unable to find a vacuum leak I changed the j take manifold gasket. Compression is good in all cylinders and all injectors are good. Any suggestions??

Well the problem is it only happens after it warms up. I figured if there was a head gasket leak from outside air it wouldn’t run so good.

Po300

That’s pretty much where I’m at.