Engine temp good but heater blows hot only 50% of time

that would be my guess. although, does it have electronic climate control? mine went out on my old 95 bonneville. it thought it was 20 degrees all the time, so we had no a/c, only full blast hot. maybe a short in the sensor wiring is giving it a weak signal from time to time.

Well I swapped the T-Stat and still no luck. I'm gonna a$$ume it's the heater coil gone bad for the front heat as the rear heat still gets good and hot. Is it a pretty straight forward swap or should I take it somewhere? I'm still learning to wrench and the wife is pregnant so she needs heat pretty bad. No heat during an Alaskan winter isn't cool.

Thanks
Mike

Sounds like the heater core is probably plugged then. If it is plugged, you should probably just take it somewhere, unless you are willing to remove the dash yourself. They're really not that bad compared to some vehicles, but it's a lot of bolts and stuff.