Ok thanks I've always wondering about that.

Well no luck with resetting the PCM. Any suggestions on my next step?
I'd basically just burn more fuel if I leave it unplugged right?

 

It won't be as efficient with the O2 sensor unplugged, it won't run with the PCM unplugged.

If you still have your programmer, might try putting the PCM back to stock, and see if anything changes.

 

So I’ve reprogrammed my computer back to stock an plugged back in my o2 sensor. With no effect truck still runs like crap.
ive traced the wires as much as I could an looked for any broken wires under the hood didn’t find any.
At this point I’m not sure what to it’s literally cut my mileage in half I was getting 12 miles to the gallon now I’m gettin 6. I’m pushing 37” an towing a 21 ft boat I was satisfied with 12. Could even get 14 if I kept my foot out of it. so I can’t just leave it unplugged. Any ideas?

Also so another thought I had was what do guys do when the delete their catalytic converter? What the do with the o2 then? Do they use the spark plug non fouler trick? An just leave the check engine light on

 

Do the non-fouler trick, and the CEL shouldn't come on.

Don't recall if this has been covered... but, how's your plenum? It begins to sound a lot like a blown one......

 

I haven’t physically looked, but I did do the Hughes pan when I replaced the engine. I will look in the morning.
If I did the non fouler trick would it potentially bring back my mileage?
Any thoughts on the cause, Could it be the computer itself? I’ve done some research I can’t find much in this issue. What would cuttin out my cat do for my engine?

Also I appreciate all the advice I get from “hey you” your always helping me out.

 

Removing the cat relieves a restriction in the exhaust, especially if it's plugging up...... Aside from that, no real difference.

Non-fouler trick probably won't affect mileage very much, if at all. Just fools the PCM into thinkin' the cat is still doing its job.

It's possible the PCM is the problem. Really need to plug a scanner in, and have a look at data. I would be curious what the PCM thinks engine temp is......

 

Ok since I have last been on the forum. I have went back to stock with the pcm, replaced NTK sensor with a Denso,4reset the pcm.
With the NTK sensor making my truck act funky I unplugged by it an ran my truck that way an went thru a s!!t ton more fuel than usual. My truck thru 2 codes. Po132 po141. After consulting someone I had wondered if I had just replaced the wrong sensor to begin with (It was the right one)so I cleared the codes , I plugged back in the sensor (at the cat) an my truck ran decent just wouldn’t hold an idle to well. It took awhile an it thru code po135, at this point I have finally received Denso sensor! So I pop that in an my truck runs good seems to hold an idle for about ten minutes then it tries to die but it isn’t throwing a check engine light this time.
It will be idiling rough an about to die, I can hit the gas an bring it back to an idle only for it to try an die again... BUT if I through it in drive the idle will pop back up an will hold steady with my foot on the brake an the same with reverse it will not do so in neutral.
An I should mention before the o2 sensor issue I could rev my truck up a few times to about 2000 rpms an let off it would idle down to around 500 rpms than jump back to its normal 800. Like it got shorted for fuel or something, but it didn’t always do that it was kind of periodic

 

Cleaned the throttle body lately? Has the IAC been replaced?

 

Throttle body is pretty clean still. I haven’t replaced the the idle air valve since I did the motor swap which wasn’t too long ago.
I thin there is even an old post of mine that mentions when I did it

 

So it has been replaced? Just a while ago? Stock, or aftermarket replacement?