05 3.4. Replaced thermostat and flushed radiator. Changed plugs last week and temperature still running very hot. Water pump?

 

How are you measuring the temp?? Digital, or are you going by the gauge.. The gauges in these (03+ are worse I understand) are known to go bad..

 

Going by the gauge. The warning light is coming on. Fan is running.

 

This is probably the intake manifold gasket. I have a 3.4 in my Pontiac torrent and that what it was it had about 85K when we replaced it. Now it seems to work ok. However I monitor the coolant level an make sure it is up. it is up to 104K now.

 

This reminds me of some other issues I have seen with the GM 60* v6.

First things first:
- Verify the coolant level is correct (and check in the radiator itself). Loosing coolant can be a sign of a larger problem (as mentioned earlier, intake gaskets, head gaskets, who knows what).
- Make sure all the air is bled out (hot air can mess with the temp sensor reading).

If you find yourself draining the system again and you do not know the age of the water pump, they are cheap (I got one for the same engine in my Grand Am for $15 and it had the better impeller). Those pumps are the same pumps used since at least the 3100's from 1994. They go ball park 100K and then you begin rolling the dice on when they begin leaking (and they are about a 15 minute swap out).