Yeah I am planning to tinker with it some this weekend as well as tuning it back to stock to see what happens.
The MAF is clean, the filter is clean, the TB is brand new, the fuel filter is brand new. I had my catts checked. I might get a second opinion on that.
I do need to read the plugs.
Good idea!

 

I'm about to give up and take it to the dealership. Tinkered over the weekend and nothing! Everything looks good. Found no problems whatsoever. "Still no codes to read" and cranks, idles, drives absolutely normal except for no acceleration. I mean none!

Today I might have stumbled onto something. I rode around with my programmer hooked up while reading some diagnostics.
I noticed that "throttle pressure" maxes out at 75%. No matter how hard I wind out the truck it maxes out at 75%. And, it achieves 75% right near the top at barely partial throttle. I can push the pedal all the way to the floor but the reading does not increase.
Shouldn't I be seeing 100% throttle pressure at WOT?
I'm guessing that means that I'm not getting WOT even with the pedal on the floor.

 

If you replaced the throttle body, you may be having an issue with the electronics at the pedal.

 

That's what I'm thinking too. I just can't figure out what the electronics at the pedal would be called and/or part numbers. If I could get that info I'd buy and throw even more parts at it.
Every search I do comes back "Throttle Position Sensor". That's on the TB and is brand new.
In my 35 years of buying and driving I've never had a vehicle run absolutely fine but have no acceleration without a check engine light or something with some direction as to a problem.

 

This may not be the case, but my '04 developed a weird stutter when taking my foot of the gas at certain times and had slower acceleration.

I changed both VCT solenoids and it's been back to normal for about a month now. Much more power and no more rpm stutter/hangup.

 

What brand of plugs are you running?

 

I could change the VCT's I guess. However the engine is running fine with no stumbling or any other symptoms.

I can't remember what spark plugs are in it. We changed them two summers ago and my memory is terrible.

 

As I recall, the brands other than Motorcraft were lasting till 25,000 to 30,000. If they are not Motorcraft, I would change them.

 

Made a huge breakthrough this afternoon. I went by a friends shop for some help.
We went for a drive. I drove my truck while he rode along with his computer plugged in and reading diagnostics as I drove.
He was quick to notice that the 1 and 2 Banks sensors were reading from 600-1000 degrees on both catts. The harder I pushed it, the hotter they got. AND QUICK!
Yep both catts are stopped up!!

I'm glad I got a second opinion. I had them checked a couple weeks ago, but all the guy did was crawl under the truck and check the temps with a lazer.

My friend ordered a pair of Magnaflow catts. I figure if I gotta replace them might as get some that'll flow.
Who knows maybe it'll pick up a little power.

 

You'll pick up some power, cause clogged cats are like towing a trailer haha.

 

I would check the fuel injectors for leakage. Something caused the cats to clog, had to be running rich.

 

Obviously I'm not a smart man in these matters, but last month I replaced my throttle body because it had been giving me grief randomly for 6-8 months. It kept throwing codes P2106 and P2135 causing the engine to go into failsafe mode.

I was told that those problems could lead to other problems like clogged catts.

I da know?

 

Update: I got my catts replaced last week. We used Magnaflow high flow catts. The truck runs much better now, even has a nice new rumble in the stock exhaust. I like!

However, while driving yesterday the "engine" light came on. I checked the codes and they are:
PO420, PO430. It says "Catalyst System efficiency beyond threshold" banks 1 and 2.

I talked to my buddy at the Speed Shop that did the work. He said that since the new catts are high flow, he needs to install a non-fowler on the O2 sensors.
Never heard of such a thing, learn something new every day.

 

Glad you got it fixed and running better.

 

Thanks! Yeah its running better that the catts have been replaced but the SAGA continues.

There's still a major issue that we are currently dealing with. It still is not running at full power. For some reason the knock sensor is receiving an input, and its pulling timing. At least 12* degrees of timing according to the computer that my buddy the tech is using.

This is why it is waaay down on power/acceleration. And this condition pours excess fuel down stream to the catts over heating them and eventually clogging them up.
That's what killed my catts.