Engine Performance problem
1997 Ford Ranger 4 cyl Two Wheel Drive Manual 251000 miles
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Since you have been so helpful regarding my daughter's civic, I guess I'll try seeing if you can help with my truck.

I have had the check engine light on for quite some time. All in all, it doesn't run badly. In the past, I have downloaded codes saying things like: lean mixture; cat-converter efficiency low; oxygen sensor pre-heater non-functioal (bank 2); etc.. I have had the oxygen sensors checked at my repair shop, and they were found to be ok.

During the past two weeks, I have been checking and clearing the codes regularly. Now, they are very consitently reading: "catalyst system efficiency below threshold (bank1)" (P0420), and "leakage diagnostic pump control circuit signal high" (P1443). (Wow! What the heck does that mean?) Might you have any suggestions as to whether I need to change oxygen sensor(s); or if the catalytic converter is bad? Any other suggestions? Thanks!!