Not long at all. He said the only code that read out was for the throttle body. I even asked whether it was likely that that could cause all the symptoms I noticed. He said first thing to do was get the part in and see if anything else showed up.
Re the other symptoms: they were caused by low battery power. The engine was running so poorly the batteries weren't being recharged.
By the way, this was A Action Automotive & Repair in Hesperia, CA.