Ford Repair: trouble code diagnoses, oxygen sensor, trouble code

Question
i have a 1993 f-150 4x4 5.0 litre standard trans
my engine lite flashes when driving but doesn't stay on solid,i pulled the code 67,what should i check for as i would like to further my diagnoses  thank you,ken

Answer
Code 67 is either caused by the AC being on when you check codes, or short to power in the circuit. Make sure the AC is off and repeat the self test.

A flashing CEL indicates a catalyst damaging misfire or a problem with the oxygen sensor that may cause catalyst damage.