got 88 pickup with 3l. truck recently started idleing really low, 500ish, after it warms up. stalls coming off freeway. it use to idle really high, say 2100 for the first 30 min or so. codes are 25 and 26, too rich and too leak fuel mixture. is this a oxygen sensor going??

 

unplug the o2 sensor and see if it drives properly. also could be your air flow senor. any way you could swap some parts.

 

unplugging the o2 didnt change anything but causing the cel to come on sooner. replaced sensor and everything was good