Replaced Throttle & TPS & now idles up and down and engine light on

Replaced Throttle and Throttle Position Sensor (bought from dealership) and now the idle goes up and down and sometimes the engine light is on. Can this be adjusted or what is wrong?

Could be any one, or more, of the following -

Plugged injector
Bad plug wire
Fouled plug
Crossed plug wires (hard to tell sometimes on V-8s that run smooth anyway)
Vacuum leak
Leaky EGR valve
Shifted timing sensor

Scan engine for codes and proceed from there.

There is a product called RXP (available here in Texas) that will clean up an engine and gas. Its pretty awesome stuff, and this coming from a person who doesn't really believe in additives.

did your car have (ETS) electronic throttle control system
the TPSis a part of this system
but you can test it by using diagnoses scan tool to check the TPS value when press or depress the accelerator pad.
so you can tell us the NO. of DTC for example(P0122)

check exhaust back pressure . can have no more than 2 to3 inch pounds off pressure. may also want to check timing marks.

Battery not charging well when airconditioner on ( also engine speed not increase when air conditioner on )

You need to purchase all the factory manuals before you
work on OBD 2 Vehicles yourself

Have you not checked to see what the codes are?

sounds like bad Idle Air control valve Not Cheap