Would I mess up my 2003 f150 4.2l v6 143000miles by disconnecting both bank 1 sensor 2 and bank 2 sensor 2 0xygen sensors? It seems to be running fine unplugged, when I had them plugged in it would idle rough and had codes p0136, p0156, p1131, and p1151. Now theirs no codes and running decent unplugged. Just wanted to know if I would damage anything
Your fuel system will stay in Open Loop and you'll likely run on the rich side.
The engine probably won't mind but the catalytic converter won't like it.
(of course you'll throw new codes)
Don't do it.
Repair the problems.
obd-codes.com
It'll take a long time to cause significant damage, but it will eventually happen. Running rich and running lean can eventually wreak havoc on both your catalytic converter and the engine itself. Too rich will eventually carbon up and ruin your catalytic converter, and could allow more gasoline vapor in the blow-by gases to mix with the motor oil. That will eventually lead to premature engine wear due to the gasoline diluting the oil, which hurts its ability to lubricate the engine. Running lean can cause your engine to run hotter than it should, taxing the cooling system and could cause heat related damage long-term (basically slow motion, cumulative overheating). The hotter mixture from running lean will also increase your nitrogen oxides emissions, which will also destroy your catalytic converter over time. It will cause unnecessary, and hazardous air pollution (nitrogen oxides react with water in the air to produce very dilute nitric and nitrous acids, helping create acid rain).
All ICE vehicles cause excessive pollution no matter what is done to reduce it. At least that's what the environmentalists say.
Carbon dioxide and water vapor are nothing compared to nitric acid. A quart of nitric acid is acidic enough to drop the pH of a 250 gallon tank to the pH of Coca-Cola or lower. The phosphoric acid in the soda is nowhere near that aggressive. Handling those acids for a living like I do makes you more aware of the effects even minute quantities can have on the environment.
No codes? I would imagine that you would still have codes with them unplugged. Which would mean you wouldn't pass an emissions test. As for damaging your vehicle, I can't say.
Unplugging dying rear O2 sensors is imho better than running the engine with them sporadically flipping put and generating p1131 (lean mixture) - series errors.
Unplugging will however (as already mentioned by other respective members of the community) have its negatives too.
It is therefore advisable to just replace these sensors asap - this is not that expensive, nor is this a job one could not accomplish himself. I myself replaced a total of 8 O2 sensors on my 2 cars. Good luck!
Thanks for the insight