Check Engine Light 1991 2.3L
The Check Engine Light comes on after about 10 minutes and at Normal Operating Temp. When it does the RPM drops to about half of normal indication and it runs rough under acceleration. Idles normal and mid range normal. Changed EGR, IAC, Throttle Body, O2 sensor and EGR Vaccum valve, spark plugs and coolant temp sensor. Dealer checked codes and advised that IAC or Throttle body is the problem. It was not still CEL. Any ideas?