Dave: You might want to clean all grounding wire terminals in the engine compartment especially the one that comes from the engine computer on the right hand side at the back. Even if they look clean, slight corrosion can cause the computer not to read the sensor inputs correctly. Do not use any grease or lubricants when cleaning and make sure chassis body surface and screws are clean as well. You can protect them with lubricant after screwing them back on after a few days and have verified all is working OK.
I had this problem. At first I thought it was IAC and even when I cleaned the IAC the engine would stall out during idling or cut out momentarily at speed as though the ignition were being turned off for a millsecond and then back on. Cleaning the grounding terminals is also good preventive maintenance.
This 'little' issue can cause all kinds of problems from performance to reliability.
You could also verify that the connections to the engine computer are OK by unbolting the connector and withdrawing it and reinserting it carefully a few times. You must pull the power steering reservoir off its retaining bracket to do this. Don't bolt the engine computer wiring terminal back on too tight either.
