Rough idle question

[agkrueger]

This fall before it even got down to 55 degrees at night my 04 started idling rough. It has gotten steadily worse now that night temps are down in the teens. The best way I can describe it would be like a gasser with one heck of a cam ( Rum Rum Rum ). It rocks the whole truck a bit.



It eventually comes out of it but it takes 15 to 20 minutes of driving. Mileage has dropped 1 to 1. 5 mpg but that is about par for winter operation. Is this rough idle normal for the 3rd gens. My 2nd gen would idle rough for a minute or so and off you go. Any input would be great.

 

[WPeschel]

This fall before it even got down to 55 degrees at night my 04 started idling rough. It has gotten steadily worse now that night temps are down in the teens. The best way I can describe it would be like a gasser with one heck of a cam ( Rum Rum Rum ). It rocks the whole truck a bit.



It eventually comes out of it but it takes 15 to 20 minutes of driving. Mileage has dropped 1 to 1. 5 mpg but that is about par for winter operation. Is this rough idle normal for the 3rd gens. My 2nd gen would idle rough for a minute or so and off you go. Any input would be great.

Sounds like an injector to me!!! JMO...

 

[rbattelle]

In very cold weather with no block heat my truck sounds like a washing machine full of rocks. I really don't get much rocking, and it certainly doesn't last 15 minutes! Do you notice any RPM variation in the tach during the rough idle? WPeschel may be right about the injector...



-Ryan

 

[agkrueger]

Well tonight it was 32 degrees going home (thats a heat wave lately) and she got up to normal operating temps and its still doing it. You can see the tach bouncing about 25 rpms. I also noticed that its enough to make the truck surge when coasting at about 40 mph.

 

[rbattelle]

Gotta be a fuel system problem. Could also be a dying lift pump...



-Ryan

 

[realsquash]

My truck has done the same thing since the day I got it. It now has 40,000+ miles on it and still does the same thing. It sounds kinda bad when it goes up to high idle at 1000rpm.



My truck also has a little bit of a surge when cruising at 65mph once in a while. It clears right up with a little throttle. Same with the goofy idle. I only plugged it in once last winter and it always started just great even down to -15F unplugged and outside. I let it idle for a minute when it's that cold, take off, and it's just perfect.



It's weird?!?!



Andy

 

[rbattelle]

When my truck is in high idle (factory high idle at 1000 RPM) and the grid heaters are cycling, the RPM varies every time the heaters kick on and off. I believe that's normal.

 

[agkrueger]

As long as there is a decent load on the engine I dont notice the rough idle. Today I pulled the travel trailer in for repairs so the truck warmed up quicker and and the idle smoothed out to almost normal. Its driving me nuts so Im going to get it in to the dealer this weekend. If it is an injector going I dont want further problems associated with that. I will keep you all posted.