Hey guys. Have any of you had your 6.7 'stumble' on take off while pulling a heavy load? This is the third trip mine had done it in a row. When starting from a dead stop, the truck almost goes dead for just a second, then picks up and runs normally. No codes, no CEL. Has only done it once while unloaded. Starting to bother me while pulling into traffic. ALSO, I have the high idle hooked up and the truck does the same thing when switching on the high idle. It bogs down momentarily then runs as it should. Filters have 6k on them. No mods to the truck as far as engine and electronics are concerned. My dealer is about 65 miles away and would need to have 5er in tow to replicate. Do any of you have any idea? It feels as if it starving for fuel for a split second. Other than this and my backup camera that I'm still waiting on, this truck has been flawless. I know it needs to go to dealer, but will be such a hassle to duplicate without camper.

 

are you able to scan for codes?

Wonder if a flash would take care of this?

How is your boost? Check all the cac hoses maybe?

 

I am assuming that you are not spinning the tires which would cause a defuel or that hill START assist isn't kicking on.

I did have a problem with hillstart assist activating when it shouldn't have and it sorta felt like what you are describing. It went away on its own - in fact by the time I got it to the dealer. (and the tech only thought that was a feature on manual transmission vehicles, but we went out to a hill and proved to him we have it on our trucks).

 

Yep. I can scan for codes but just haven't done it yet. No CEL though. The best way I can describe it is if you've ever driven a Mercruiser inboard V8 and the way the engine is killed for a split second when shifting from forward to reverse. That's what it does. A momentary "kill" then it normally picks up and goes on with no other symptoms. However, yesterday the road coming out of the campground is steep at the stop sign. When starting off, the truck did it 3-4 times in a row. Almost completely killing the engine.
Dak may be onto something. It just may have something to do with the hill assist as I haven't noticed it on flat ground. Or if I have it is so quick I couldn't feel it.

 

Mine did something similar to this once. Not my 2011, it only suffered from the occasional har shift. My 2016 did a random power loss at a red light which made me believe the truck was going to stall. I figured it was air in the line or something.

 

I know that if you are slighty on the brake it will hesitate...thanks to Toyota floor mats.

 

Scott, I was going to mention something about that, along the lines of driving with "two feet"

 

On my 11 I had a stumbling, just as we were leaving, to where I thought it was going to die after loading and headed to Colorado, so that evening in Clayton NM, I changed the fuel filters. since it had been about 8k, as I always carry a set, always. I never had a problem after that. Just a thought here.

 

Nope. Never have, never will

 

I've thought about fuel restriction as well. I didn't have it with factory filters, and these are OEM. And I've actually thought about changing them to see if that clears it up. But 99% of the time it's when the 5er is hooked to her. Just puzzling.

 

Let me know if you decide to have your dealer take a look, Monty; you know I'd be happy to help out however I can. How many miles are on your truck currently?

Crystal

 

Crystal, currently I have 16,800 miles on the truck. I currently waiting on my new backup camera to come from Ford, but my hitch is already there. Just waiting to make the 30 mile trip to that dealer. However, anything diesel has to go to the owner's other Ford dealership about 65 miles from home. I have the South's largest Ford dealer 4 miles from my home, but they stay so busy is hard to get my truck back in less than 3 weeks. My buddy just went through that with them.
I know you'll be happy to help and may end up calling on you. Thank you for the offer!

 

You're quite welcome, Monty! I'll be here to help, if needed.

Crystal

 

Push the traction control button so that it is off, and see if that makes a difference.

 

Monty , FWIW, about 27K towing a heavy toy hauler out of 74K, never had a stumble.