2006 Mega w/ 5.9 is surging without a load at cruising speed.

No codes. Just an intermittent surge when cruising with no load.

If I mash the go pedal, it perks right up. Lay off the go pedal and surge starts again.

Sensor(s)? Injectors? Fuel Pump?

Where to start? Taking it to the dealer today...however it is out of warranty...depending on what the problem might be.

I have a 1,400 mile roundtrip to start on Thursday...want to nip this in the bud.

Thanks in advance.

 

Mine does the same thing when in cruise contol. It only seems to do it when going downhill, as soon as the cruise applies fuel, it goes away. I just don't worry about it too much. If it starts to do it too bad, I just cancel the cruise for the downhill, then resume. Is yours a downhill thing, or is it constant?

 

Not a downhill problem for mine. Constant problem (slight problem now, but slowly getting worse) when not under load or cruising (with or without cruise).

The crazy part is that I was going to upgrade the entire fuel system at the end of next year when the engine/drivetrain warranty runs out. This is too early. I hope it isn't the injectors...that could cause other problems, but so does a bad sender or pump .


Dealer is booked up and can't look at it today. Will find out tomorrow hopefully.

 

BTW, Air and Fuel filter are new...just changed the oil and filters yesterday. Also, new front brake pads, bled the brake lines with new fluid, and installed new front shocks.

Test drove it after doing all of that and now it is surging. Rechecked the filters and the oil level...all good.

 

Whew thought mine was the only one that did that in cruise on the downhill. Try trailer tow button, seems to make it stop on mine. I did the same thing though, I just quit worrying about it.

 

OK. I feel like a dolt.

It appears that the "surge" is actually a "pulse" that is only manifesting when the A/C is on. Also, the A/C is now blowing non-cold air. It appears that my surge issue is due to my A/C going belly up. It isn't 100% dead but is on its way out.

It is only 98 degrees right now, it is not a big deal.

Going to Kansas Thursday is not in the cards for my Mega. Will be renting a Suburban or something...that has a working A/C...especially since the forecast for Wichita, Kansas area this weekend is 100+ degree weather.

But in good news...the parts for my gas grill arrived today...after they were backordered two months ago.

BTW, my new Bilsteins from Geno's feel great in the Mega...well except for the hot air coming from my A/C.

 

check the map sensor o ring on the intake manifold, this made my cummins surge under light throttle.

 

Check the wires for rubbing down by the oil filter and a/c compressor. Common problem. Can also cause rough idle.

 

Definitive answer to surge/pulse problem (for me):

It was the A/C clutch (which is non-serviceable and integral to the compressor). 2006 MegaCab 3500 5.9L G56

If you get a surge/pulse...turn off the A/C and see if it goes away. If it goes away then you have your problem - A/C compressor/clutch assembly.

Compressor clutch went out and burned up the compressor 49,XXX miles.

When it went out it started a surge/pulse feel when driving. Thought it was a grounding issue or FCA problem initially - until the A/C quit blowing cold air.

$900.00 at local dealer to change compressor/clutch (as mentioned non-serviceable clutch), refrigerant, purge/pack lines. Had them change the serpentine belt and pulley tensioner (self provided those two items). Heck, $356 was labor.

Was trying to find an aftermarket compressor and clutch that was bigger and more robust for the MegaCab. Couldn't find anything. So it now has a new Dodge/Chrysler replacement unit. The Suburban I rented to drive to Wichita has a better unit and more space to cool. But I digress.