I took a trip out to Connecticut (1.5hrs of driving). It was almost all highway miles and my SVT ran very well out there. When I pulled up to a friend's house and let it idle as I waited for him to come out, however, the car started spark-knocking and slmost stalled! I gave it tiny bit of throttle and it woke right up but felt a little weak and was still spark-knocking a tiny bit when it came back ot idle. It definitely wasn't a rattle of a bracket either. Once I started driving on the highway it cleared right up again but right after I left the house it felt REALLY weak.
My car is bone stock and has a Stock Ford Tune. I always run 93 octane too. I checked to see if my millage reflected any sort of issues and I averaged about 32MPG with two people and 2-300lbs of crap in the back hatch area on stop+go Rt6/44/etc so I guess she was running perfectly on the highway... Was it heat saturation that caused this? It was a cool night with no rain and temps were in the same area as usual. What gives?