CEL came on,went off and came back on. 1993 4runner 3.0. Truck runs fine,but cant seem to find the problem,any suggestions?

 

25 could be

AIR/FUEL RATIO LEAN INDICATOR--LEAN SIGNAL SENT TO ECU FROM O2 SENSOR

--INJECTOR FAULT(S)

--FUEL PRESSURE

--OXYGEN SENSOR

--AIRFLOW METER OR MAP SENSOR

--IGNITION

--ECU

31 could be

MANIFOLD AND/OR AIRFLOW METER SENSOR SIGNAL CIRCUIT

--AIRFLOW METER/CIRCUIT

--MANIFOLD PRESSURE SENSOR/CIRCUIT

--ECU

32 could be

--AIRFLOW METER SIGNAL (VANE-TYPE)

--AIRFLOW METER./CIRCUIT

--ECU

24 could be

--INTAKE AIR TEMPERATURE SENSOR SIGNAL--OPEN OR SHORT IN INTAKE AIR TEMP. SIGNAL

--INTAKE AIR TEMPERATURE CIRCUIT

--INTAKE AIR TEMPERATURE SENSOR

--ECU


I'd start with replacing the 02 sensors then go from there. That's the most common problem it seems.

 

Changed the plugs,NGK's and Ngk wires,Toyota Cap and rotor,Air Hog air filter.Put on new muffler and tail pipe, Ran great.Then codes showed up.The check engine light went off, and then came back on.

 

Try clearing the ECU and see if they come back on.

 

on the 93 4runner, pull the EFI fuse?

 

You can just unplug the terminal from the battery for about 15-30 seconds.

 

Indeed. EFI fuse or + battery connection.