Hey guys, I tried doing a search, but nothing really works out when I do..
This doesn't happen all the time, but recently when I am idling my RPM will go from 500 to 700, and keep going up and down. If I put the truck in park it'll rev up to 1000rpm, then back down to 500. Can anybody help me figure this out?

 

Dirty throttle body perhaps??

 

Quite possible.. this is my first time owning a 3rd gen truck. I bought the truck at 100k and I've put 10k on it since I got it. I don't think it's ever had a tune up.. so this weekend I'm gonna be cleaning everything, new plugs, wires, oil changes, all that good stuff. Let's see if that'll fix it!

 

In that case the TB is gonna be a clogged up mess and quite probably an issue but it sounds to me like a full tune up should be in your near future. A clogged PCV would also cause the issue...