Finally I have something to post about.  I haven't had any issues so I've been lurking.  Sadly this could be an expensive one?  Let us discuss... 

 

Today I'm out driving to an appointment, all is well.  Take a right hand turn and hear a loud bang, more-so a metal clunk (almost sounded like a u-joint snapped on the driveshaft).  I immediately notice a slightly odd idle at the next stop light.  Go about another block after I make the turn and the truck starts bucking/limping, practically no power.  I noticed a little bit of white smoke out the exhaust when under load (but not idling).  Made it off the road into a parking lot and I'm thinking textbook bad VP44.  During this entire time I never got, and still do not have, a CEL on the dash.  I turn the engine off.  Next, I turn it back on and the vehicle is now running normally and has been ever since.  

 

Only getting a 1683 DTC with my scanner and nothing else, which I find odd.  I am not sure in which module the DTC is in because my scanner has odd labels for the ECM/PCM.  But I will soon confirm which one it is in.         

 

My past DTC's in the month of May were:        (These DTC's below are not currently showing just thought it would be worth mentioning):

 

P1682 -Replaced alternator and code has not come back.  Confirmed bad alternator by bench testing it.

P0122 -Code came back 1 week later after clearing it.  Cleared it once more and did an APPS reset simultaneously and the code has not returned. 

 

Pretty puzzled at the moment.  I can go out right now, crank it up, and it runs normal.  No bucking, smoke, rough idle, loss of power, and no CEL. 

 

I'm starting to think ECM but we'll see.

 

Thanks Fellas

 

 

UPDATE:  Getting no codes now. Not one.

Edited May 30, 20186 yr by sooxies
update

I would associate the loud bang or metal clunk is mechanical and not associated the engine running rough unless something in the engine broke. I experienced that a couple years ago. Sounded like someone hit the front of the truck with a 5 pound hammer as hard as they could. Truck ran fine before and after. I rebuilt the front brakes about 4 months later and found the front u joint was gone. Only made that noise that one time. Not sure what would cause the engine to run bad in that circumstance though.

 I did loose my ECM 8 or so years ago, No loud noise just ran a little weird one day and the 2 days later you could not drive it. Still ran but undriveable. I have of late had some surging issues, MAP issues, and other slight running issues. I do believe these are wiring issues possibly with splices in the engine wiring harness. I am about as electronically challenged as they come so I do not know this for sure, but believe this is causing many folks weird issues.

On 5/30/2018 at 9:06 PM, dripley said:

I would associate the loud bang or metal clunk is mechanical and not associated the engine running rough unless something in the engine broke. I experienced that a couple years ago. Sounded like someone hit the front of the truck with a 5 pound hammer as hard as they could. Truck ran fine before and after. I rebuilt the front brakes about 4 months later and found the front u joint was gone. Only made that noise that one time. Not sure what would cause the engine to run bad in that circumstance though.

 I did loose my ECM 8 or so years ago, No loud noise just ran a little weird one day and the 2 days later you could not drive it. Still ran but undriveable. I have of late had some surging issues, MAP issues, and other slight running issues. I do believe these are wiring issues possibly with splices in the engine wiring harness. I am about as electronically challenged as they come so I do not know this for sure, but believe this is causing many folks weird issues.

This is just a little update...

 

Today was my first issue since this thread was started.  Was driving 55-60 on the freeway and the truck bucked/surged.  This happened within a matter of half a second I'd say; it was really quick (just one single jolt forward).  The motor did not die (might have come close...not sure) and it came back to normal within this very quick moment.

 

Once again...no CEL.  I did hear the door chime ping once (as if there was a dashboard warning).  Zero codes on the scanner.

 

Edited June 10, 20186 yr by sooxies

many years ago i experienced some bucking. By that i mean like you just flipped the engine off for a split second and it came back on as hard as i had the throttle pushed. Happened so fast I could not respond to it. Is that what you are experiencing? That is what I learned to call bucking. I also experienced some dead pedal issues at the same time. I saw no CEL thru my instances of this but did go to a shop with the problem. Their diagnoses Turned up no issues other than very low fuel pressure, 5 psi at idle and pretty much 0 psi at WOT. I installed a booster pump to the fuel system and the issues went away. I also at the time had an in tank fuel pump.

 

Is your fuel pressure good? Getting mine up solved the above problems, as described above, for me. 

On 6/10/2018 at 6:18 PM, dripley said:

many years ago i experienced some bucking. By that i mean like you just flipped the engine off for a split second and it came back on as hard as i had the throttle pushed. Happened so fast I could not respond to it. Is that what you are experiencing? That is what I learned to call bucking. I also experienced some dead pedal issues at the same time. I saw no CEL thru my instances of this but did go to a shop with the problem. Their diagnoses Turned up no issues other than very low fuel pressure, 5 psi at idle and pretty much 0 psi at WOT. I installed a booster pump to the fuel system and the issues went away. I also at the time had an in tank fuel pump.

 

Is your fuel pressure good? Getting mine up solved the above problems, as described above, for me. 

Let me rephrase a little from my second post...

 

While driving 55-60 on the freeway, the RPM's started to drop almost to the point of the engine dying.  Almost instantaneously, the RPM's jump back up to normal which in my feeling caused the truck to lunge forward.  This is all within half of a second approximately.  You felt it as if you were slowing down then immediately felt that lunge forward once it regained it's normalcy.  I'm confident that the metal-like clunk I heard the first time was something in the drivetrain as a result of the truck jerking forward.  I inspected everything visually and felt for anything loose (all was normal).

 

 

I've been recently wondering if it is possibly a fuel-related issue.  I'm thinking I will warranty my fuel pump.  I supposed it wouldn't hurt assuming I can make it happen.  Sadly the sending unit went out for my fuel pressure gauge.  Fuel pressure was within the normal range when the gauge was last working (which was before this happened).  Due for a new fuel filter so I have another one on the way and Autometer said that the sending unit is serviceable so I need to get it sent out. 

 Mine was like you had a toggle switch that would kill the motor and you flipped off then immediately back on. There was no lunge forward just a hard hit. This happened more when the motor was under load as in towing the fifth wheel. It was a bit unnerving when it would happen the jolt was pretty strong.

 I did have it happen a few times long before the other issues when I was hard on the throttle and empty but a fuel filter change fixed that. I was still learning about the truck then. Even then it acted the same just not as big a hit when the engine came back after that spit second of off.

 If you are due a filter I would give that a try maybe it is just that simple.