Hesitation in Lexus SC430

My scenario is the same as Mr Buffalo Mikes that I found on the forum… Was there ever a direct answer for this problem… I have had the car seen a year ago they said it was the throttle body, water pump, thermostat, not to drive it… The car was not running hot. But coolant was low so refilled and stayed full. I called Lexus and they said the throttle body wasnt the problem though they had not looked at it… Toyota looked at it. The car has driven fine but now it hesitates just as Buffalo Mike has mentioned… Any ideas… Here is the post from Buffalo Mike…

I have a 2002 Lexus SC430 that I have owned since it was new. Great car with virtually no problems until about 2 months ago. I have 53K miles on it. A couple months ago it sparadocialy started to hesitate. I back out of the garage when the car is cold, put the car in drive and give it gas. Sometimes it hesitates before it kicks in. Sometimes this will happen when I am a block or two from my house. It is almost like the gas isn’t getting to the engine, then it kicks in. It has never stalled out. A week ago, while I was driving 360 miles out of town, it did this same hesitatation at least 6 times while I was going 80 mph on the highway and at least 100 miles into my trip. While driving at 80 mph with my foot on the gas, the car would decelerate a bit, before it would kick back in. This would last from 2-6 seconds. Lexus dealer could not duplicate the problem and since it never stalled they have no computer data, so they were useless to find a problem