What the What?

[Jeffofalltrades]

Hello everyone, I'm hoping for some insight into an acceleration and hesitation problem on my 2011 1500 4x4 SLT 4.7 flex fuel with 127k. I have been replacing, testing all the bits.. Timing chains and guides, intake gaskets, valve cover gaskets, lifters, cam, crank, MAP sensors. K&N Air filter, Plugs, wires, coils measured good. Compression 140's 145's. The top of this motor is spotless, the cams are healthy. Ive taken apart and cleaned the APP.(Gas pedal). Ive got normal pressure at the fuel rail and all injectors are pulsing. This problem sometimes clears up and the thing leap's into the power, kind of like going in and out of limp mode. Then next thing I know its bogging down and then if I hold pedal 3/4 it will slowly gain rpms then suddenly around 3-4-k it lights up like it should. Other times no RPM above 2-2.5k. While chasing this problem one avenue was clogged Cats and after deciding it must be this, they got emptied and non foulers downstream and no codes. The Cats were not clogged...Thats another frustrating part too because I never get any codes... Im like , whats the damn OBD good for? lol.. Its never overheated, at least since I've owned it. Bought it at 100k. 127k now. When i did the lifters I did notice one rocker arm slipped in really easy and pondered on that for a bit but i dont hear any deserters hangin around in the galley after running. Another strange thing is I notice on decel truck seems to slow pretty fast, as before all work done it would carry on. I also did the 4th mobile one oil and filter change and just replaced the front brakes last night thinking they might be binding but no change. Rear brakes are fine. Idles pretty damn smooth but i think it could improve. What I have not done it the EGR, fuel pump and throttle body sensor or exhaust gaskets - (No sound or visual leaks). Mileage last said 14mpg , at 1/3 of full tank used. Plugs all gapped correctly.
I'm really hoping one of you sharp guys or gals out there has the magic answer or just some insight to this riddle. As we all know,It aint to much fun doin all this work for the most part, but to not get a proper final result is chappin my hide!
Maybe a Valve seat jumping in and out comes to mind but dosent coincide with symptoms. I dont think..
What U say? TIA... Side note... $4k for new Cats in CA.. Nope!....

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[Daw14]

Have you tried fresh OEM Mopar o2 sensors ?

Only use OEM sensors in any vehicle for the chance of best results.

Infrared point and shoot temp guns a great for checking brake rotor and drum temps, as well as lots of other things.

corrosion on/in main harness connections seems to become an issue after a decade or about . Start disconnecting and inspecting for crusties .

 

[RamDiver]

Hi Jeff, to Ram Forum.

What is the history behind this hesitation issue?

Has it always had this problem since you've owned it or is this new?
With 127K miles, there are plenty of places to look but I'd avoid using the parts canon approach because it will be expensive and unsatisfying, to say the least.

Have you pulled off the air intake and looked into the throttle body?
Don't use any metal tools but open the butterfly valve, and shine a bright LED light inside.
Can you see any visible buildup or gunk inside or on the backside of the butterfly valve?

There are many threads on cleaning the throttle body, be sure to use a cleaner that won't cause grief with the sensor inside.

Also, read this thread on using Redline SI-1 fuel additive, I'm a satisfied user.

Official Redline SI-1 thread.

OK sorry forum but I do not believe Corey aka hemi395 or I had ever brought a si-1 thread here. We did do one at bobs, just never officially did a thread here on it. We were going to wait until we did more tests and never got around to it, but thanks to another fellas work on the net I think...

www.ramforum.com

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[Jeffofalltrades]

Thank you, Michael. So, it started losing power and would bog almost every time trying to pull out of a driveway about a year ago accompanied by loud valve train. I don't put that many miles on it but in the last year It's been used on my property doing a lot of stop and starting with short run time. When i got the truck, I did the 100k service on the motor and trans and it ran flawlessly. That was probably three years ago.
I forgot to mention I did do a throttle body clean with correct cleaner. There was a little build up and general greasyness/dirt but to be honest I didn't deep clean it, thought it looked pretty good. Worth another round?
Ill check out redline thread shortly.

 

[GTyankee]

use Throttle Body Cleaner, not Brake Cleaner
Brake Cleaner will remove the special coating

Do Not spray any sensor, or any electrical part around the throttle body

GOOD LUCK