1990 V6 LE hesitating, Check Engine Light Codes 25 and 26

[ycartf]

We have a 1990 V6 LE Camry sedan (that my teenage daughter uses) with a CEL 25 and 26 (which I already cleared). The vehicle also has diminished power, drastically-reduced gas efficiency, and when sitting at a light idling in Drive it sort of idles low (about 900rpm) and feels almost like it is lurching just a little in time with the engine. I looked up the info on the CEL codes, and found the following:

25 - Air-Fuel Ratio Lean Malfunction - Injector circuit, Injector, Oxygen sensor circuit, Oxygen sensor, ECU, Fuel line Pressure, Air flow meter, Water temp sensor, Ignition system

26 - Air-Fuel Ratio Rich Malfunction - Injector circuit, Injector, Fuel line pressure, Cold start injector, Air flow meter, Water temp sensor, ECU

The plugs, wires, cap and rotor, and fuel filter (among other things) were all done 4 years ago and 34,000 miles ago (although at the time I did not know to use NGK plugs and used Bosch.) The oxygen sensor has not been replaced since we bought it about 75,000 miles ago too.

I just wondered about which components you would check first (or that someone has experienced causing this). I know this is just a general description, but I was hoping someone else's chase in the past would help me narrow the chase down. Thanks in advance for any advice or suggestions (and especially shared experiences). Also, is there more than one oxygen sensor on this model? I only see one in the illustrations in the manual.

Thanks,

Tracy

[white90dx]

Replace the plugs first to see if that helps/fixes the problem. Incomplete burn of the air/fuel mixture can cause the problems you are describing. If not, then maybe it is the O2 sensor or something else.

-Charlie