1998 Pontiac Grand Prix 3.1 SE
I am having problems figuring out why I am having cyinder misfire I have replaced spark plugs and wires removed fuel injector and clean them check for wires frail have a computer to check engine codes but still have misfires can anyone point me in the right direction tia

When does the vehicle misfire? At idle? Under a load up a hill? Does the CE flash when there is a misfire? P0300 set?

Have you checked coil output at each terminal with a spark tester?

It is amazing what is out there in auto technology for less than 50 bucks.......you can plug in a WIFI or Bluetooth adapter into your ALDL connector, and read data on your smartphone....all kinds of data are available , as well as plotting data.....it makes life a little easier if you know which cylinder is misfiring,,,,,,most data shows misfires per cylinder.......

Secondary misfire is caused by plugs(using OEM?), wires, coils, or ICM......you could have a lean misfire caused by a bad intake gasket or upper plenum gasket....you could have a leaking injector misfire....poor flow from an injector......bad injector harness/connection or PCM.....or a mechanical problem with compression......

But checking coil output would be my first test if wires and plugs were replaced....