CEL code 21 and 27

[hambob]

I have a 95, 4x4, 3vze, California emission(2 O2 sensors). I noticed a decline in gas mileage recently, the CEL did not turn on but I checked for codes anyway. I got codes 21 and 27 which is strange because I replaced my O2 sensor(after the cat) a year and half ago, after the CEL came on. The other symptoms aside from gas mileage are hesitation when cold, I can feel surging under light acceleration that seems to go away when warm, lack of power until about 3000-3500rpm, after which it seems like the non existent turbo kicks in and after driving on the highway then stopping for 30 min or so she'll start but run rough(low idle) for a minute then back to normal. The only other related repair I performed was I had to fix the wires to the O2 sensor(after cat) after they fell on top of my exhaust(they were not ran properly after a tranny replacement), melted and blew my EFI fuse when I was on the highway(that was fun). I was very careful when repairing the wires, I soldered them, used heat shrink tubing, taped them and then routed them properly using wire that protector stuff. I am wondering if the codes could be the symptom of a bad cat or something else. Any ideas would be greatly appreciated.

Thanks,
Hamish

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