Andrew Dafoe

Have an 08 Silverado and just got a new fscm put in It drove like crap before and after so I don’t think that was the problem I think the truck is in limp mode but I don’t know how to tell. I checked the codes and this is what popped up I watched a video and someone replaced all their spark plugs and it fixed Heres the thing, sometimes I’ll be driving it and it all of a sudden drives fine but that’s not until 15-20 minutes after