I have a 07 1500 4x4 quad cab. From day one it has idled a little rough. I figured the motor mounts were a little tight or it just needed to break in and it would stop. I now have about 10,000 miles on it and the problem seems to be getting worse. Any time I stop at a light or put it in park the truck shakes slightly and then stoppes and then shakes again. Is that normal???? The other thing that I have noticed is that most of my axle and rear diff are compleatly covered in rust! I was my truck fairly often and make sure to spray the road salt off in the winter but it still has tons of rust. I look at other peoples trucks and they aren't near as rusted. What could be the reason for that?

 

Not sure about the rough idle, but on the rust, surface rust is normal, as long as it's not pitting or flaking. My truck has about 3500 miles and the driveshaft already has surface rust on it - it's just something that happens to bare steel.

 

Surface rust is very common, especially up north, salt will tear up a vehicle like nothing else. What engine does your truck have? 4.7L or the hemi? Could be as simple as dirt in the throttle body, or on the 4.7L, the throttle position sensor is notorious for causing low and rough idles.

 

I have the 4.7, is the throttle position sensor fixable or do you just have to live with it? I doubt it would be the throttle body since it did it from the factory.

 

Sensor can be easily replaced, and isn't very expensive.

 

great thanks for the help. I'll call the delaership tomarrow, it should be under warrentee

 

Awful soon for a throttle position sensor to go. There was a TSB on the '06s for rough running at idle and extremely low speeds. Possible the '07s have it too. I believe the fix was an updated PCM flash. Go see the dealer, you should be well within warranty.
As far as surface rust, it is normal, especially on the axles and driveshaft. As a matter of fact you want to see some rust on the driveshaft, means you got a steel one. Some trucks ship with an aluminum one and they have been known to grenade riding along the highway. You can ask Hemiyellow about that one...

 

so I called the dealership this morning and told them my idle problem. They asked if I had a check engine light on. I said no. He said if there is no check engine light on they cant do anything because the truck is so computer controlled that there is just nothing they could do. "I mean there's just no way to find it unless the computer tells us". "there's no adjustment we could do". "that truck is so sensitive that if something was wrong the check engine light would be on, if you forget to put the gas cap on it tells you". So is this guy just jerking me around or is he right?? would a check engine light be on????? This is why I do all my own maintainance, I dont trust any dealer service department.

 

It's a cop out, but many of them are taking that stance. I got a buddy in Ga., when I was up there in June he asked me if I would take a look at his '03 Hemi, it was idling really bad, no acceleration at all, just running really poorly. Dealer told him it needed a tune up, they did it, to the tune of $400. Got it back, no better. Complained and they told him to take it back in. They test drove it, agreed that it was a "tad" rough, but they tuned it up & without a CEL there was nothing they could do. Told him to drive it until it got a CEL and take it back. WTF kinda answer was that!
Turned out the throttle body was clogged as bad as I've ever seen. Cleaned it and it ran like a top!
Moral, you can have a bad problem without the CEL going on and many dealerships are useless!!!

 

Yes it's a cop out, there is a huge amount of things that can go wrong with a obd2 vehicle without setting a check engine light. There are also pending codes your vehicle will store and will be picked up by the right diagnostic equipment. There also should be a techline the dealer can call to find out if there are any issues and how to diagnose and fix them if there is something wrong. If it does it all the time it shouldn't be that hard, the hard problems we see are the intermittent issues that happen like once a month. Sometimes then it's a guessing game and the customer has to be patient for that stuff