I have noticed just recently in the past few days my idle has developed some sort of issue.

If i rev my truck in neutral and let off the throttle pedal the truck goes below idle and then jumps back up to idle speed. It jumps back so hard the whole truck jerks a little to the side. The idle is set at 750 with a/c on.

If this is normal, what would cause this not to happen. As the truck just recently started doing this. Nothing has changed in at least 10,000 miles.

 

no one elses truck does this? Or does everyone's?

 

mine did that/ still does if i jam the throttle real quick
i have changed out the overflow valve, and fuel filter in the last few months and it seemed to help my idle stop doing that. i also have my idle bumped a hair higher than what it should be to prevent it from stalling
....its a shot in the dark, but i hope this helps you out some
-Josh

 

10k miles ago I replaced the OF valve and filter, surely it hasn't already lost its tension? Might try a filter change and see what happens. truck still runs and pulls normal. Gonna adjust the valves this weekend guess i'll do some indepth searching then. thanks for the reply. Oh by the way, I know its super small but the truck in my avatar is my actual truck. Tried to get pics in gallery but there not in it yet.

 

Ha,
My truck started doing that same thing, but only when cold, at about 3000 miles, and now at 177000 its still doing it. Dealer, and several diesel shops have never been able to figure out what causes it. Oh well...

 

My dad's 97 does it when cold , i actually kinda like it, makes me remember how much torque is there , don't see any gasser engines shaking the whole truck.

 

My truck does it at all temperatures. Yes it sure does remind you of the massive tourque on tap. I kinda like the way it sounds too, just wanted to make sure that it wasn't a warning sign or something.