I have a 2003 Dodge Ram 1500 Quad Cab, I bought it used with 34000 miles on it. First I'd like to know what the cold idle RPM should be when it's sat for an extended period and is first started, I thought I read somewhere it's 1100 RPM and I thought that's what mine used to be, over the past couple of weeks however I've noticed it's around 900 RPM. My second question is, sometimes I'll start it cold and it will idle fine, other times I will start it and it's rough and gets only worse when I put it in drive or reverse. The past month it's been especially troublesome because the MIL light has came on in the dash, I haven't taken it anywhere to get the code read yet, but it has done this so far three times, the past two times I've just disconnected the battery and it has resolved the problem but then eventually it'll return. Thus far my troubleshooting has been, changing the oil, oil filter, air filter, cleaned the Throttle body, checked exhaust for any sulpheric smell. All of this to no avail. I called a dealer and they told me this could be due to needing new plugs wires etc. I have not had time to change all of that yet but will if anyone thinks it would benefit in this scenario. I don't recall owning a vehicle in the past that required needing new plugs at only 36000 miles or roughly thereabout, my last vehicle was a Chevy S-10 which of course needed new head gaskets at only 90 thousand miles but I do recall keeping the same plugs in it for over 50 thousand miles.
It should also be noted that I have the 5.9 litre engine. I have read some places where there is an update to the TBS Sensor however when I brought this up to the dealer they didn't sound to enthused about it and made it sound more like it was in need of either the tune up or it had an air intake problem or something, I don't remember specifically what he said.
If anyone has any suggestions please let me know.

 

aren't tune-ups (plugs, wires, caps and all, at least plugs and wires) recommended at 30,000? that's what I've always heard...50,000 seems a little hight to me...but I have a 2005, never heard of the MIL light. Ask that laramie05 guy he knows EVERYTHING!!!