My truck has had a badly running engine for a while. It's like something is loose in fuel system (or something else) I thought it might be fr the AFC live I've put in, it allows you to adjust the AFC from inside can, on the fly. So I've been meaning to take it in (good diesel mechanic in Sac area?) What the engine does is power fluctuates often and almost instantly. It can be bogging down and then instantly starts running well. Today at a stoplight I accelerated away and glanced at pyro, it went up to at least 1500 degrees while also bogging down, barely moving and barely accelerating. I went to gas station where I am now. I started it up after I kind of got my head together I was upset that I was stuck in traffic and had to continue driving. Now it seems ok idling, guess I'll start driving again but I'll drive gently and hope it doesn't do it again.