K CODE

hello, to get stright to the point i have a 04 f-150 fx4 5.4 my two front cat's are bad, pulled them off and they where thorn up pretty bad. If i where to remove the front ones and leave the back one's intack will that cause any problems that you know of? Like troubles codes for example, and if so is there anyway to by pass it so the computer doesnt read them not being there? Hate to buy new ones i know they, are not cheap. Thank's for any suggestions.

PS: ONLY MODIFICATION I MAD TO THE TRUCK IS A "FLOWMASTER" MUFFLER 40 SERIES, STOCK PIES NOT DUAL EXHAUST AND A K&N AIR FILTER.

02Screw

I say leave em off and buy 02 simulators for the codes.

KC5-0

Where is the 02 sensor? if it is after the second one then you will be fine. If not you will have to move it to after the cat.

02Screw

There should be two sets of 02 sensors a set before the cats and a set after the cats. He will prolly need to get 02 sims for the second set seeing as only one cat is doing the work of 2.

TheJMC

Replace them and weld a bung in each of the replacement pipes for the front O2 sensors. That is what I did and I even pass emission sniff tests.

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RadioMan

You may not get trouble codes using 02 sims but your
MPG may drop into the crapper. 02's regulate the amount
of fuel to dump into the engine at different times the
engine is cold, hot, working hard, not working hard and
so on.

I'd just bite the bullet and replace the cats (Y pipe) and
have it over with, K CODE.

Hay, I don't like all this electronic control either. Give me
the good old fix it yourself days but we gotta live with it
so might as well go by the law.

Just my 2 cents worth guys..

TheJMC

O2 sims only work for the rear O2 sensors. The rear O2 sensors only monitor the Cats. They do not effect the drivability of the vehicle.

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