Hi Tom Troy. Welcome to the forum. First of all, to do the head gasket, the battery had to be disconnected. That means the Engine Computer "lost its mind". It lost its memory and has to relearn a bunch of stuff including "minimum throttle". All of the things that have to be relearned are done automatically but minimum throttle requires a set of conditions to be met before that will occur. Until it is relearned, the computer will not know when you have your foot on the gas pedal and when it must be in control of idle speed. To meet the necessary conditions, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.
When the Check Engine light turns on while driving, there will be at least one diagnostic fault code stored in memory. You can make the light flash out the code(s) by cycling the ignition switch from "off" to "run" three times within five seconds, then counting the flashes of the light. The starter must not crank when cycling the switch. If there are no codes, the light was just turning on in response to the computer expecting the engine to stop running.
Be sure it's the Check Engine light too, not the Check Gauges light if you have one.
Tuesday, November 9th, 2010 AT 9:52 PM