Hesitation when accelerating. when tac is over 2K RPM the car runs o.k. but the vehicle shakes and rattles when accelerating under 2K RPM. someone said it may be the TPS but I am thinking it could be the IDLE Air Controller or possible misfire in cylinders. Please help

I would be looking for a vacuum leak. Check that none of the hoses have been split or disconnected when you were working on it before.

There's many reasons this can happen, but start simple. Fuel pump may be failing. Usually under load they can not supply the fuel the engine is demanding. (Up hill acceleration is a classic example). change the fuel filter first, if that doesn't not correct the problem, test fuel system pressure. (:

use a couple of quality injector cleaner in the tank
run fault codes
remove and clean injectors
check fuel pressure

Well, those codes definately are related to why your vehicle will no longer accelerate!

P2107 is "Throttle Actuator Control (TAC) Module Processor"
This code means that the TAC portion of the Powertrain Control Module (PCM) has failed the self-test.

Posiible causes:
> TAC motor circuit harness shorted to ground
> TAC motor circuit harness shorted to voltage
> Damage Electronic Throttle Body (ETB)
> Damaged PCM

P2110 is "Throttle Actuator Control (TAC) Forced Limited RPM"

This code is informational only. It sets in conjunction with other throttle actuator control codes (like P2107 above). It is just letting you know that the PCM is limiting RPM due to a TAC malfunction, (So it doesn't do a "TOYOTA" on you and run away!"

it could be a transmission problem like drive couplings inner or outer

you will need to have someone hold it at the rpm than rattles and get under car and find it, the exhaust is the first item to check

need to be more specific with the exclamation light... color, description of what the light looks like with the exclamation.

Red usually means your brakes,
Orange should be coolant related

I had the same problem on my 2006 Lucerne and it was the engine mount located on the front of the vehicle behind the radiator.