Don't replace the EGR valve, it's an expensive component and without proper diagnostic you can end up wasting your money.
Before you replace any parts, how's the battery. A bad one can cause weird things with sensors. If you have a digital multimeter, measure DC voltage across both terminals and you should see around 12.6 volts. If it's too low (less than 12), then you need a new battery first.
The TPS is located at the side of the throttle body, just after the plastic intake tube running from the airbox and has a 3 terminal connector on it. Make sure to use the proper phillips head, a suitable socket and a RATCHET rather than a regular screwdriver as this can, sometimes, strip the head on each bolt. You might want to use some soft(green) or medium(blue) threadlocker on the bolts.
The injectors are on top of the heads and there are 3 injectors at each side (front and rear of engine compartment). They have a yellow ring on them and a 2 terminal connector. First make sure the wiring is OK by disconnecting one at a time and measuring DC voltage between each terminal and a good ground; you should see around 12 volts (or battery voltage) with key on and engine off (KOEO).
Oscar.