Cadillac: 4.9L Deville Hesitation., intermittent faults, throttle positioning sensor

Question
I have a 93 Deville with 83,000 miles. I'm getting a hesitation after I press the gas pedal, almost like it gets no fuel for a second, and then kicks in. I cleared all the codes, and unfortunately there are no codes coming up now. I tried to pull codes while driving and getting the hesitation and still no luck. I recently replaced the coil, Ignition Control Module, and the Idle Control Motor, and all three seem to be functioning correctly. My mechanic says the Ignition timing is on, but I'm not so sure that is not the problem. Any ideas? Thanks in advance.

Answer
If you look down inside the throttle body you will see that it has a blackish residue on the side walls and on BOTH SIDES of the throttle plate. Clean this area with a suitable cleaner such as carb cleaner or similar spray can agent thoroughly and see if it improves.

Possible intermittent faults are:

TPS = Throttle Positioning sensor.
Carbon buildup in the EGR passages.
EGR valve.