Over heating I have replaced the thermostat water pump radiator plus cap, the tempature gauge still wiggling what's next?

The impeller could break loose from the shaft. You would have to remove the pump to find out for sure.
Could be a blockage in one of the passages too.

Is your 3800 producing normal heat? If so, the temp sensor is probably bad...If not, try replacing the radiator cap...if your system has air trapped inside, it usually runs hot, not cold...the heat is the key to functioning properly for you...Your radiator is a 4 stage huge system that normally cools very well...if you have heat, I still think your temp sensor is bad...ask to see one at your parts store, will help you to locate it. Hope this helps.

Can you explain your problem more ?
The thermostat should be at the end of the upper or lower radiator hose to block flow to the radiator. The spring must be on the engine side to get the engine heat to open.

no heat engine running hot sound like faulty thermostat which is sticking closed.if thermostat stuck closed no coolant can circulate through the engine block and radiator causing no heat condition and engine overheating.replace thermostat and radiator pressure or surge tank over jug cap see what happens.

this is probibly a blockage in the radiator or water pump issue start by flushing the radiator,then check that water is flowing thru the radiator and water system.

Hello, Do the fan(s) come on when hot? Blow out the radiator core with compressed air (from the engine side) to clear it of bugs and other debris. Make sure the radiator is full to the top (when cold) and check the radiator cap seal rubber and the over-flow tank and tubing for leakage. It's possible that the water pump impeller is slipping on it's shaft and not pumping water properly. Remove the thermostat temporarily and remove the radiator cap. Remove some of the water so that the level is somewhat below the cap bottom, then start the engine and watch for rapidly moving water. That will show that the pump is moving water well. Allow the engine to heat up and keep track of the water movement. Shut the engine off at low end of 'normal' on the temp gauge and replace the cap so that it doesn't blow out boiling water into your face. Replace the thermostat and top up the water when cold again.

Thanks

Check the sensor which controls the cooling fans that cools the radiator it prevents the engine from over heating and allows the temp gauge to stay at normal range.recently had problems with my 2003 impala overheating it was the sensor had the thermostat replace as well.

your thermostat probably stuck closed.when you cooled it down,it opened again.change the thermostat.

did you try replacing the radiator cap and the temp sensor?

You mentioned that the cooling system had no pressure when you removed the radiator cap. Somewhere the system is loosing pressure. Have your cooling system pressure tested. Have it pumped up to 20psi and watch for any water coming out somewhere. By the way the lower hose and the upper hose are 2 different temps., this suggests the thermostat could very well be stuck. Take a peek at the under side of the water pump with a flashlight. If you see a trail from the weep hole, there is your problem, a water pump going bad.