hey i just read that you replaced the core before i posed my last reply. haha i guess i should read all the posts. so nevermind on what i said in my last reply it won't be of any help now haha

I checked the temp last night on the way home. 10 minute drive and it was 140*f on the floor vent, outside temp was around 46*f. On the way to work again this morning I let the truck warm up for 10 minutes and then drove 10 mintues to work. Outside temp was 21*f and heater on the floor was 120*f.

It's freezing inside of the thing and temps are no where as low as they will be this winter.

Yeah I had bad heat for a while as in almost no heat. I payed to have the heater core flushed and that fixed it for the most part. When I did the A/C work I changed the heater core also and now I have heat that when I put my hand up to to the vent started feeling like it was burning my hand. I'm happy with how my heat works now.

But I just put a heater core in it last weekend. All the blends doors work like they should. What else could it be?

Anyone else have any ideas?

How did you confirm that the "temperature" blend door is completely sealing out cool air so you only get air from the heater core?

Well I checked to make sure all the doors were moving the whole way. How can I check what you sugjest?

What about the water pump? The manual says that bad water pump won't be strong enough to push the water through the core? Sounds like it would makes sense that you are not getting good flow.

If it were a bad water pump the engine would most likely be overheating as well.

It could over heat, but not necessarily. A water pump is not the same as an oil pump. It is a centrifugal pump that moves water, but does not build pressure like an oil pump does. A worn pump may not provide the flow needed to keep the water moving through the heater core. Coolant can still flow through the system keeping the engine cool just from thermal properties without the need of a pump.

This is directly from the FSM:
If the floor outlet air temperature is too low, refer
to Cooling to check the engine coolant temperature
specifications. Both of the heater hoses should be hot
to the touch. The coolant return heater hose should
be slightly cooler than the coolant supply heater
hose. If the return hose is much cooler than the supply
hose, locate and repair the engine coolant flow
obstruction in the cooling system. Refer to Cooling
for the procedures.
An alternate method of checking heater performance
is to use a DRBIIIt scan tool to monitor the
engine coolant temperature. The floor outlet air temperature
reading should be no more than 4.5° C (40°
F) lower than the engine coolant temperature reading.
OBSTRUCTED COOLANT FLOW Possible locations
or causes of obstructed coolant flow:
² Faulty water pump.
² Faulty thermostat.
² Pinched or kinked heater hoses.
² Improper heater hose routing.
² Plugged heater hoses or supply and return ports
at the cooling system connections.
² A plugged heater core.