Toyota Repair: Celica-same old problems, now with check engine light, air fuel ratio, radiator hoses

Question
Had this '93 Celica GT (2.2)for 10 years now. Love her but she always seems extremely hot under the hood. Occasionally, there has been a real problem and the temp gauge has responded ie. cracked radiator, ruptured radiator hoses, and the latest water pipe crack. She still will put a blister on you for checking the dipstick. All said my other concern is the bogging in low gears (for years now)and now the check engine light intermittantly goes on (code 25)Recent servicing includes compression check (170 to 172),new ignition coil, replaced water pipe, fuel injectors cleaned and new air intake filterr system. The code covers quite a few things and before replacing everything I just wanted to bounce it off of you first. She still gets 30 mpg but the hot engine(doesn't show hot on gauge) and the bogging down on acceleration has been an issue for a long time. What do you suggest doing next? She is the daily driver and just keeps ticking (bless her heart)Thanks

Answer
The code#25 is an oxygen sensor code which indicates that the engine is running in a lean condition, the air fuel ratio is too lean, this may be due to some sort of air leak on the intake side or even an exhaust leak, before replacing the O2 sensor the lean condition should be diagnosed, if no ther problem can be determined then the O2 sensor in front of the catalityc converter should be replaced.