i have a 96 blazer that I just picked up, had a leaking heater core, so I replaced the core....fun....now i am still having some heat issues inside. i can hear the heater door opening and closing but not really getting any heat inside. no air bubbles in the coolant system, one thing i did notice is that when i have the radiator cap is off and look inside when i gas it, it doesnt spray super hard through the fins like my other blazers have done in the past. pressure tested everything to make sure there were no leaks, both heater hoses get hot, but also lose heat and get hot again. truck is not overheating and has a new thermostat..... any insight would be helpful, i checked all the vacuum lines under the dash, if there is something i could have missed, please pipe up. Thanks guys