06 1500 Megacab, 135k, one owner truck just purchased....month into owning it I would notice after hitting a stretch of semi rough road and climbing a slight grade, it would cut out once, then it started cutting out a couple times and now sometimes it will cut our several times and run good for a while.....but it always seems like it does it right after clearing a rough patch of road and always while on the throttle.

Also, the ETC light flashed a few times and sent me into limp mode.

Firestone originally diagnosed the issue as a throttle body and bad battery, but didn't fix the issue although the ETC issue hasn't resurfaced, but the cutting out is still happening. Its been back at Firestone and Ive spoken with the tech who seems to be pretty knowledgeable about wiring and ground issues....nothing can be found as to why it doing it. They refunded my money.

Any suggestions?
Truck will not misfire sitting in my driveway idling, idles smoothly and doesn't have any other issues except for the cutting out.

It feel like a voltage drop from the ignition but its not a single cylinder because of how hard it drops out or maybe a momentary fuel pressure drop but its very quick.

Any suggestions?

 

Logging the data while its doing it would probably give you a good clue as the where the problem lies.

 

Is this a 5.7L Hemi or a 4.7L?

2wd or 4wd?

I doubt it would be the Throttle Body b/c that should be Drive-By-Wire.

My only other guess would be a bad ground or power connection at the fuel pump.

When you said the light would flash do you mean the Check Engine Light? Or a different light?

When was the last time you changed spark plugs?

What kind of spark plugs did you use the last time you changed them?

 

5.7, 4x4....the ETC light (small lightening bolt light), spark plug age unknown, only put 2k on it since Ive had it.

Any idea of where the fuel pump ground is located?.....and wouldn't a loss of fuel pressure throw a code?

 

Don't think our trucks have a Fuel Pressure Sensor, so short answer would be no, I don't think so.

It would throw a misfire code.

If I was you, I would go buy 16 shiny new COPPER CORE Spark Plugs and replace them all just to be safe.

They are cheap enough that it's worth the time and peace of mind.

I'd suggest starting there if you cannot purposely recreate the problem, and data log it.

 

Replacing the plugs might be a good idea, but I doubt that is your problem. Spark plugs don't systematically shut down at once. If you had the ETC light flash, you should have a code. I would suggest having a dealer pull codes for you. It could be your crank sensor, or any number of things. One thing for sure, it is electrical.

 

perhaps the fuel pump itself is having some issues with the vibration. The jarring of a rough road can cause the pump to stop briefly. Ive seen it in some fords before but all pumps are pretty much the same so it could happen.

Its either that or wiring to the fuel pump or crank sensor or maybe the PCM connector.

 

This can be easily seen if you were to install an LED on the supply line to the fuel pump. Put the LED in the cab and when the truck cuts out, see if the LED cuts out. You can get a Bi-Polar LED and hook it up so that if you have a broken ground, the LED goes one color and if the power side breaks, the LED goes another color.

 

Not a bad idea, just make sure the LED is rated for the current.

Spark Plugs are cheap enough that is a good starting place to eliminate it.

It will also help to narrow down if the coils are potentially the problem too.

I've seen the connections on the Coils corrode inside the rubber insulation and then have problems when hitting bumps.

 

I have run into several issues with NGC controllers doing nutty stuff like that related to ETC specifically. The LX (300, Charger, Magnum) cars were the worst in this regard, BUT if you happen to have a PCM that is not original, then it's possible yours could have been remanned from an LX core.

With the truck running grab the wiring bundle up close to C-2 connector on the PCM first (orange keyed) and/or the connector itself and give it a hard up and down wiggle, push in/pull out on it. See if you get any symptoms. Not hard enough to break it, but be firm with it. Do the WHITE and BLACK ones that way also.

Best suggestion I can give you from here. Gratz on the refund from Firestone. The ones here will just tell the customers tough chit usually and send them to the dealer. PepBoys is the same way. I guess the business zones differ greatly.