So... I dont drive my truck everyday, the girlfriend drives it during the day because im sick of commuting it 50 miles both way.
But last night I was blasting up a hill, 4th gear WOT and all of a sudden my heat comes on. for the last 2 months my heat has not worked well (not hot like it used to be) I thought it was just the selector valve behind the dash... whatever.
anyways the heat comes on (I had the fan on) and so I shut it off and cruse for another mile then pull over. everything looks fine, no leaks, water temp was about 170 (high for my truck) and so I continued on. drove it for the rest of the night no issues.
girlfriend texts me saying it has a knocking sound this AM, intermittent, does not go up with rpm. I told her to watch the guages, and make sure they stay in their range, also told her to check the oil incase the front IP seal popped, oil was right on.
anythign else I should be worried about? she just says it has a slight knock at idle, any opinions on what it could be?

seems you've dropped some serious coin on it lately 