so i had a problem with my temp guage acting funny, goin all over the place before it settled down to normal. SO i replace the temp sending unit and it was fine for a day or two. WEll, today during a shoppin expedition
, i got back in th truck after being out of it for ten minutes and it had npo heat at all. It is in the 20's right now! the guage read cold and i know that it is hot. so if the heater core was plugged woiuld it cause this nonsence because i dont think its the thermostat? Any suggestions?

