hi, i have a 91 toyota pickup with engine codes 25 and 26 and rough idle.
replaced the factory o2 sensor with a bosch, and replaced wires plugs cap and rotor. ran better for a couple days, then rough idle is back and cel with 25 and 26 again. higher rpm doesn't seem to have issues...maybe slight loss of power. uses slightly more fuel than normal.
thought maybe the bosch o2 sensor is inadequate? ordered a toyota oem o2 sensor to replace the bosch.
AFM checks out with ohm meter according to service manual.
EGR stalls engine when i attach a vacuum line to it apply vacuum...although it feels gurgly when i suck on it to test.
any advice is greatly appreciated