I have a misfire on cylinder 4, 99 Silverado 5.3 385k, I have replaced fuel injectors, spark plugs, swapped coil packs with other cylinders, swapped plug wire, fuel pressure is about 58, compression test on cylinder is about 150. When running live data i only see misfires on idle, if under load driving misfires zero out. Any ideas where to go next

 

could be a failed injector circuit. A good diagnostic tool can do an injector balance test.

https://troubleshootmyvehicle.com/gm...oid-light-test

or a leaky intake gasket