Car starts and runs normally for various time periods (15 to 20 min), suddenly engine will slow and will not respond to throttle to rev above 1000. I pull over, then in a minute or two throttle response returns. This cycle repeats as I make it home. Check engine light comes on. Socket 2 codes: 213 (throttle switch full load setting faulty or grounding short) 223 (signal missing from idle air control valve) Socket 6 codes: 234 (TPS idle signal faulty).
I have replaced the TPS and adjusted. Pulled the idle control valve and cleaned it and bench tested it's function (OK). Tracked down the wiring in engine compartment and made sure harness connectors were good to the TPS and Idle control valve. Checked ECU grounds, cleaned ECU contacts.
If I clear the codes, the car runs & idles perfectly until the next episode of "limp home" performance and code setting. Have 345,000 miles on this wagon. Never replaced the ECU, and starting to suspect it. What do you folks think? Thanks for any suggestions.