Help check engine light on

[Bhplumber]

I just fixed a broken exhaust bolt. Everything went easy. Started it back up and it ran fine. I did a few other checks on the truck and then took it to town and noticed the check engine light is on. Now its running rough at low RPM. It also cranks alot before it fires up. It also idles irratic up and down until you put your foot on the brake to put it in gear. Any ideas????

[HUMTECH]

MAF sensor unplugged?

[Bhplumber]

After a few cuss words and just walking away for a minute. I thought about it for awhile and realized when I moved the exhaust manifold out of the way to remove the broken bolt I probably damaged a spark plug. Sure enough I cracked the porcelin part of the back plug. I was planning on changing them anyway since I had just bought the truck and wasnt sure what had been replaced. I picked up a set of AC Delco plugs and some 7MM wires, Problem solved.