have my heads/cam ls1 on a snap on scan tool and it's reading misfires on all cylinders especially cylinder 4, my question is is it doing this because of the heads/ cam and the tune, or do I have a problem. I've never had it on a real time scan tool and have no reference to look back a determine if it is reading different. the car does seem to have a miss but not as serious as this scan tool would indicate. anybody ever have their hands cam tuned ls1 on a real time scanner and read misfires?

 

Cam lope will look like misfires to the misfire detection routine that is looking for the smooth crank rotation the stock cam provides. Most cam tunes will have misfire detection desensitized or eliminated completely.