I have a 99 4dr Hoe with the l31 that I installed a cam, long tube headers, wit cat and egr deleted. My problem after cam install and retune. I get random misfire code p0300.. when I use my buddies Scanner I catch all cylinders misfiring at idle only. It doesn't feel like its misfiring. I checked for vacuum Leaks and haven't found any. I asked Justin from blackbear performance said it was possibly do to crank relearn, which I have done with no success. Can you guys give me any ideas?
I have emmisons soon. I need to take care of this..
I have another issue also that when I decelerate the truck. It stays at a high idle. Depends on the speed I go.. if I hit 40 mph it stays their for a while then VERY gradually it drops down. Even if I brake, I don't think this is normal.

Just in case when I installed cam I also replaced timing chain kit, head gaskets, valve springs, and spider with updated ones also had heads checked and resurface since I was replacing the gaskets
After cam install i replaced idle air control valve, throttle position sensor ( I taught this would fix her) then mass airflow it went out.

Thanks in advance.

sounds like you need a tune

Thanks SS. I'm going to have to find someone local to tune it