So i have a code po420 which my GF' uncle said my cats gone (which it is, its gutted) and its running rich and something to do with the IAC or something, could these last two problems be with the cat being gutted? not sure how as they just came up a month or two ago and its been gutted for a few years.

And now my mileage is weird, i fill up on mondays, work is about 60 miles a day so thats 300 or so a week, but by thursday or so im almost at 1/8th of a tank and at 270-280 miles and ive been averaging it at 26-29MPG so how is this? I mean at 23 mpg i should get at least 287 miles per tank but ive been averaging 26-29 mpg shouldnt i be getting at least 320-340ish? or is the gas gauge that in-accurate?

Could this ^ be associated with the p0420? Im clueless, and also i must note, everytime i get on it hard i smell gas or something of the sort and its awfully nausiating sometimes lol, what might cause this?

 

that smell could b from ur cat or muffler.. i had the same smell when i needed a new cat.. since ur is gutted idk tho... try getn a new cat and or muffler.. thats what i did and i got aobut 50 more miles on my car even more witha a new o2 sensor..