ChuckT

04.5 3500 dually NV5600

Runs great, tows great, cruises great until engine goes to idle. Then all hell breaks loose. Surges with RPM going up to 1700 RPM and smoke out the tail. It will do this only at idle; under load and not under load. As soon as accelerator pedal is pushed all symptoms go away.

Its got to be fuel or air control...FCA, EGR?

Any ideas?

Darn thing is down-right dangerous to drive in stop and go traffic.

44Bisley

Not sure of issue or cause, but my 2007 has done this to me twice now. Only at idle and only for a few seconds (10-20 seconds I'd guess), then no more. Have started researching this and have seen various causes. No help, I know, just sharing that I just started having a similar issue. I have only owed the truck for a couple months now, so not sure if this has happened before.

dezeldog

I've been having the same issues for some time now. However mine is a high miler at 432K and counting. Truck has been completely maintained as it should be....so this is somewhat of a mystery. Hoping that somebody solves it soon.....TIA Jim

dezeldog

Also I forgot to mention that the truck is throwing NO codes.

saggonwaggon91

Hook it up to a scanner, not a code reader, and see what the TPS is doing when it surges. It also may have pending codes that wont show up with the code reader until they store.

dezeldog

Will do.....Thanx

Jim

44Bisley

Mine has started acting up a lot more recently, now occurring at all speeds and with no link as to the cause. Very erratic and unnerving as you never know when it's going to happen. A few times the truck is nearly undriveable and more than just an annoyance. I have ordered a FCA in hopes this is it. Will report back if it is.

ChuckT

I ordered an FCA from Geno's Garage and it showed up yesterday. After install I'll let everyone know if it fixed the problem or not. I hope to get to this today.

Peace....

ctjstr

I'll be interested in the solution. My 04 with 240,000 recently started surging just after startup. It will go from nearly stalling to about 1700 and back. Does it for a couple minutes and then seems to run ok. However, there is a slight hesitation now when accellerating from a stop.

johnh

i have a mild surge at idle. it really bothered me until i found the cause...........

AC was turning off and on!

ChuckT

Installed FCA:

Connector was broke at the FCA so I think it was making intermittent contact causing the surge. The connector at the harness was undamaged...sombitch!! It's quite possible the FCA still works but I just replaced it. After install truck runs perfectly and idles at 750 rpm when cold and around 650 warmed up.

Whew!!!...What a relief...

Chuck