A few weeks ago I took about a 3 1/2 road trip and when I got where I was going, my truck would idle horribly up and down between 400 and 1000rpms when I'd come to a stop. Drove around there for a few days and it eased up a bit. Drove great on the way home (70mph / 2k rpms) but as soon as I got home at the top of the off-ramp it was idling even worse. Just drove it for a couple of weeks. No codes ever came up. Did replace the air intake temp. sensor last Wednesday. Afterwards it idled perfect for a couple of days. Then went on another 2 1/2 hour road trip and when I got there it was at its worst. Actually died several times while there after dropping to like 300rpms. Restarted each time though and made the trip back home. Hasn't died since but still not right at all. Any ideas???

 

mine did that to. just make sure all your vacume hoses are good, and replace you pcv valve. did the trick for me. also take you egr valve off and make sure its working properly

 

The 03 4.7 doesn't have an EGR. Still a good idea to check vacuum hoses and might be a good time to pull and clean the throttle body. Do a search for throttle body cleaning. I'm pretty sure there is a tutorial on how to do it. Every once in awhile mine will do the same thing. I usually just have to shut it off for a few minutes and it'll start up and be fine. Repeats every so often.

 

I would replace the PVC valve and clean the oil tube. I have a 2003 4.7L Ram 4x2 and I replaced the PVC and it worked fine for a little bit. It then continued to rev up and down at idle after about an hour or two of driving. I then cleaned the oil tube, and it worked fine. Make sure to lift the poorer plug thing. Its inside the oil filling tube and gets clogged up with old oil. After I cleaned that out, I sprayed and cleaned the PVC valve with degreaser and have had no problems.

 

Thanks to everyone for their posts and suggestions. Luckily it hasn't given me too much trouble since I first posted the issue. It has idled bad only once since then. But I haven't been on the interstate either, just local driving.

The PCV valve makes sense and may be the issue. When I took off my oil fill cap I had to clean off a bunch of built up crud on it which was collecting down in the top part of the fill tube as well. My brother in law told me that the build up was notorious on the 4.7Ls and to not worry too much about it. I wiped it out but I may still have some of that stuff built up back into the PCV valve itself. I'll clean everything out and then clean out the throttle body like you all have suggested and post the results afterwards. Thanks again.

 

Clean the TPS and IAC sensors...also clean butterfly valve of TB as you stated