It has been really cold here today in Dallas (below freezing). Got in my truck to go home, started it up, and it started to "surge" as it was idling. Didn't really notice a huge fluctuation in the tach, just heard the engine. It would do this for a little bit, then stop, then do it again for a shorter time than the last. After a few minutes it started idling smoothly. Any ideas? Truck is stock, idles fine otherwise, just does this when it's cold. 2007 F-350, 6.0, 6 speed. Thanks!

 

If it's anything like mine when I start mine in Mid-Missouri cold weather...noticable when below 20, the truck sounds sick when started for a few minutes. I don't know if I would consider mine a "surge" though so I don't know if mine is the same as yours but mine clears up after a short period and idles up like its supposed to. As long as your experiencing the same as mine it's nothing to worry about. I know since you live in texas you might not have a block heater but you might check to see if you do because when cold weather sets in these things are a life saver...or truck saver I should say.

 

It was around 28 today...now that I think about it I think I remember it doing this on one other really cold day. When I start it, it's like I'm sitting there with my foot on the gas pedal and pushing it down, then releasing, pushing it down, releasing...on and on really fast. If I kick the high idle on, it smooths right out. I do have a block heater on it but I don't have a way to plug it in at work....

 

nut1605 it "sounds" normal from what you describe. as a precaution I would run some anti-gel like power service and perhaps crack the drain on the bottom fuel filter on the frame rail to make sure you have no water in the fuel system.

 

Thanks for the advice on draining the water/fuel separator, I hadn't thought of that. I do run Diesel Kleen in it....maybe I will try an extra strong dose next time. It hasn't done it during any of the previous 2 winters I have had it, and it has gotten much colder than 28 when I used to take it back to NM...so if it is normal, it's not normal to this truck. Thanks for the replies!

 

What weight oil are You running? Just curious.

 

Rotella 15W-30....never had anything else in it.

 

The reason I ask is because of the injectors in our 6.0's. They use oil to make them fire, if the oil is thick and cold it may contribute to a minor rough start. I hope that You don't have a "stiction" issue w/an injector. You may consider changing your oil to a synthetic 5w40 to help. And just to give peace of mind I would check the voltage on the FICM.

 

I would check out the ficm voltage. Refer to the ficm test procedure in the tech folder. I was having very rough cold start until warm, then it turned into some surging, and in the end it was a no-start situation. Replaced the ficm and it fixed everything for me. The truck has much more zip now, and it sounds the same cold starting in 19 degrees as it does after being run for 2 hours. Perfect.

 

Yes, a stiction issue would be bad. I have thought about turning to synthetic, but wasn't really sure if the benefit was really worth it. If I do switch to synthetic, is there anything special I need to do? Maybe a stupid question, but how do I check the voltage on the FICM?

On a different subject, I notice the exhaust on your truck is exactly what I am wanting to do on mine. How does she sound? Is it loud and obnoxious or a sweet rumble?

 

Nevermind, found it in the tech folder...thanks gmhorse

 

Its definately a sweet rumble! not obnoxious at all. MBRP bolted up so well even a Caveman could do it!!

 

There has been some confusion about whether the 48 volts should be during cranking, or or after running. When testing the FICM the voltage should be between 47-48 volts with the key turned on engine off, while cranking, and while running. If it is below, remember to try the FICM fix before you try to replace it. It may correct the voltage.