What could be the cause for occasional overheating of a 1998 Cadillac Concours DeVille?

It has a 4.6L engine, overheats occasionally. There is no odd smell from the exhaust pipe and no leakage anywhere. Pump works fine, antifreeze stays the same level. Could either the spark plugs, wires, or the ignition coil be the cause?

P.S. When driving, sometimes it feels like the power is reduced and the engine is vibrating slower than usual.

Tnx in advance!What could be the cause for occasional overheating of a 1998 Cadillac Concours DeVille?type how to check over heating car into search box

how and when does it over heat in traffic or out on freeway does it do it in a short trip or in a hour or soWhat could be the cause for occasional overheating of a 1998 Cadillac Concours DeVille?check out your thermostatWhat could be the cause for occasional overheating of a 1998 Cadillac Concours DeVille?Radiator cap defective,worn plugs(excess gap),Fuel pump pressure to low,possible fuel filter may need changing,Air dam under bumper could be gone,vacuum leak at fuel pressure regulator,water pump seal may be starting to fail.