92 camry, no heat and when engine warms up it wants to die. Changed thermostat but no difference could it be a plugged heater core?

Was lack of heat in the cabin the only reason you changed the thermostat? Were the radiator hoses hot (or very warm) to the touch before you changed the thermostat? Were the heater hoses hot before you changed the thermostat? Did you get a check engine light and code stating that the engine was not getting (or slow getting) to operating temperature?
Getting heat from your heater depends on a blend door actuator letting air flow through the heater core in the HVAC unit. If your radiator hoses are hot, your heater hoses are hot, and you have no trouble code indicating the engine is not getting to operating temperature, but you are not getting heat inside the car, you need to check your blend door actuator or the control unit for the heater.

Possible plugged heater core. Check heater hoses when engine at operating temperature. Both hoses should be close to the same temperature. If one hot and one warm/cold, suspect a plugged heater core. A backflush will be required to correct the problem if it is plugged

If the heater valve operate properly then the line to the heater core is plug.
Check & replace or flush.

Good luck

Mai

low heat at idle is farly normal for camry, i had alot of complaints about th that at a toyota dealership where i worked

See if your library has a Stratus shop manual and check the heating system chapter. You didn't say if the engine was reaching operating temperature or not. If the engine is warm but you are not, I would say the problem is in the heat exchanger somewhere. If your engine is cold, you can't really expect the heater to get warm, now can you. Then you have a different problem to chase.

Lack of water on your floor means your heater core is not leaking. It could still be plugged somewhere. The fact that you get some heat initially, but it turns cold when you turn the fan on, sounds like a lack of adequate warm water to the heater core to me. If the engine is warm, it could be a circulation problem of some sort.

if its been a while since the thermostat has been changed then change the thermostat first.this maybe all it is.then when the car has run enough so it should be hot then grab the heater hoses they should be the same temperature.if not then the heater core is plugged and will need to be replaced.however this is rare on a camry but does happen.

is it flowing into the heater core check line at heater core when engine is warm hoses should be warm as well if they are not its possible thermostat is stuck.

Get it warmed up, and with the heat on and running, feel the coolant lines that go from the engine compartment through the fire wall to the heater core. They should both be hot. If not you may have a plugged up heater core. If you can remove both hoses and flush water through it, sometimes this will unclog the core.

Location of components...

With the car warmed up,feel the heater hoses,are they both warm/hot near the firewall in the engine compartment?If they are both warm/hot,then the heater core should have circulation through it and it may be a "blend door" issue in the heater a/c assembly.If they are not warm/hot then the heater core could be dirty and plugged up and needs to be flushed.
If the above does not help,a drain and vacuum of the cooling system and vacuum refill will remove any trapped air.
Sometimes,clamping off the top rad hose and holding the engine rpm at 2000 rpm will force trapped air out of the heater core.(Watch temp gauge when trying this)
Lastly,a NEW thermostat doesn't mean its working correctly.