Try turning the hazard flashers on and off a couple times, see if that starts your signal lights working. If so, replace the hazard switch/module.
They should all impala's from 2000-2011 have the same bolt pattern 5x115
A 2003 Impala does not have a timing belt. It has a chain.
Use hand signals.
the egr valve on a 2004 impala should be on the drivers side of the engine. It is located at the rear towards the firewall.
it should be under the hood in the fuse box in the engine compartment or but the passenger door.
the coolant level
They should be 6x9's.
It should tell you in your owners manual.
not sure what causes it, but sometimes my signals will just not work. with lever still in position to activate signal, push button for hazards. then put signal lever in "off" position. turn off hazards. signals should work. temporarily anyway.
Yes they should. I have a 1994 impala and I havge 22 inch rims on it. But I do have low profile tire though.
160 to185 degrees
It should be for the fuel pump.