When you start a new topic there is a text box to enter the model number of your appliance.
Most spray arms are somewhat loose and appear wobbly to some extent. This does not necessarily mean it is defective. When a dishwasher doesn't clean well, there are a couple of things to consider:
Is there enough water?
You can test this by starting a cycle and allowing the unit to fill. When it is washing, open the door and observe the water level. It must reach the heating element for the pump to work well.
If the water level is not up to par, replace the water valve.
If the water is up to the element, then the pump and wash system may have problems.
How hot is the water at the sink?
Do you have to run the water a long time to make it real hot?
Does it get to at least 130o
? (be sure, use a thermometer)
Also measure the tub water temp to see the difference.
Check both spray arms for foreign debris.