A little problem

[JWBFX4]

Alright I have a 2006 fx4 5.4L with a gryphon running bills custom 87 performance tune.

So today I was driving to the lake maybe pulling about 1100lbs in the 87 performance tune and when I pulled into the gas station my truck started idling horrible. So I shifted to park and the same thing. Also with reverse and neutral. I thought maybe it was a fluke, so as I was leaving I went to get on it, to possible clear it up, but the truck felt like it would not get out of its on way. So I pulled over into the next gas station because the truck had not much power going down the road and felt like it was going to die at red light. I set the truck back to level 2 and it has all cleared up. No problem ideling or getting up to speed.

I also checked for codes and it came back with none.

At first I thought it could not be the tune since it didnt do it from the beginning, but now I am skeptical since changing the levels helped. Also I have no clue if this is in relation to the problem but the other day after having my truck sit for a while....maybe a week in the hot sun, when I cranked it up, the truck made a clunk? sound possible.

Any thoughts?

Oh and the rpms were steady while it was acting up.