I have very low heat at idle. Truck has 130kmiles, studded, black onyx hg, egd delete, sct x3 with street tune from RCD, new oil cooler, new tstat from advanced, ford gold coolant. I was going to work this morning and when i slowed to a stop noticed that the heat was cool. when i got to workshut heat off let egt come down turned heat on and had hot air for about 10 seconds, then it became cool again. no puking, no tea kettle sound. Does anybody have any ideas? I hope it isnt hg's again, they were done about 2kmiles ago.