1996 Pontiac Grand Am need suggestions

I just had an oil change. After I drove out of the garage my car started stalling when taking off from a dead stop. Like the acceleration would try to be there and then the car stalls. I can restart it right away after putting it in park and slam on the gas to get it moving. The car has good pick up and seems to shift fine on the highway. I called the mechanic and he claims he did not unhook the battery. He wants me to come back and pay for the car to be hooked up to the computer to find the problem. Says maybe its the idle control motor. Does this sound right? Why did my car start having this issue after an oil change?