Maybe I'm just being paranoid, but I've noticed a clack/ping when my truck is under load at a low rpm. I've noticed it the most if i'm parked with the truck facing down hill and go to back up. When the rpm drops slightly below idle as im engaging the clutch it will let out a clack clack clack (sorry for lame description) It has never done this until this winter and does it warm or cold. I've also noticed it will do this occasionally at around 1500 rpm while driving down the road. Anyone else had this problem?
Also if the the truck is not plugged in and I go out to start it and let it warm up it idles very rough until it gets warm, it never did this before. If its plugged in its fine.