Truck Misses/stumbles randomly, usually while accelerating...

[Krew]

Hi all,

Been trying to figure this out for a couple of weeks now and haven't really come up with anything.

My truck just recently started stumbling/hiccuping/missing ( I dont really know how to describe it) when accelerating. It seems to be fairly random, sometimes I can drive for a full day and it doesn't happen.

When it happens, it only last for maybe half a second before returning to normal. It starts and idles fine as far as I can tell. No codes either (pulled via Edge Insight).

I've order a new Cam/Crank shaft position sensor as well as a new MAP hoping that will cure the problem.. but I'd like a more programmatic solution if possible rather than just throwing money at a wall hoping something will fix the issue.

Other info: Brand new air filter, new fuel filter and water sep ready to be installed, However the ones currently installed only have about 5k on them.

It started happening right after I installed a new rear tow receiver, could I have pinched a wire or something that would cause this?

Please help...

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[Krew]

No ideas? (ten characters)

 

[jgillott]

I have had similar issues that were caused by the wiring harness leading to the map sensor.

 

[jjdiesel]

Need info on your truck. Fill out your signature so that the guys know what they are looking at.

 

[Krew]

Need info on your truck. Fill out your signature so that the guys know what they are looking at.

Sig updated. Thanks

 

[p-Bar]

Could be the FCA . Try dumpimg some 2 stroke oil in the fuel tank and see if it goes away.

 

[Krew]

Hi All,

Figure I'd drop in and give an update. I changed the filters and the problem went away. HOWEVER, its now returned and even a filter change isn't helping. The FCA is only a few months old so I'm not convinced that is the issue... but it could be. My next thought is possibly either a CPS or the APPS... I can probably order a new FCA just to eliminate a bad part as well.... Thoughts?

 

[TCDiesel]

Its likely not the APPS/CPS/FCA. How many miles on truck?

 

[Krew]

92k.........

 

[Alan Reagan]

Have you tried taking the Smarty back to the factory configuration to eliminate the possibility it is giving you a problem.

Also, I had a similar problem on my 2010 and it was the fan clutch. It started putting spurious signals on the engine load signal line causing the engine to miss. The dealer had replace the throttle body, injectors and other parts before finally allowing a real mechanic to look at the problem. I’m an electrical engineer and the mechanics allowed me to look at the signal analyzer and I could see the pulsing signal on the engine load line. He was noticed the fan clutch engaging and disengaging with similar timing to the fan clutch. The fan clutch was faulty and replacing it solved the problem. I could make it miss with the truck in park by increasing the rpms to about 1900. The mechanic thought at first that it was a transmission issue thinking the TC was locking and unlocking causing it to feel like the truck was missing.

Also, look at all of your engine grounds and make sure they are clean.

 

[Krew]

I think it may have been the Smarty. I realized it was not the latest software so I went back to stock and the problem disappeared ( for now), I've since upgraded the software on the Smarty and reloaded my tunes and so far so good. The truck is actually running WAY better now too. Fingers crossed that was the issue. Also, just yesterday replaced the original OEM batteries I couldn't believe they were the originals but the date codes don't lie. The tired batteries MAY have played a role as well.. but who knows. So far so good.