Have you tried a different key? How much "stuff" is on the key ring?

 

Thanks for the reply .....

The key worked fine right up till today , I only have bare essentials on it (key fob , camper shell key , receiver hitch lock key and a aluminum carabiner to attach it to my belt loop) , so no weight to speak of , as I understand about heavy key rings pulling on the ignition , but I did not think this was the case , like I mentioned , it was like if you shut off the engine , then forcefully turned the wheel so there was pressure on it , then locked the column , that is what it physically felt like when I went to turn the key when it first did this
, I thought I had to move the wheel to take the pressure off it , but this was not the issue as it needed the key itself moved out just slightly , like I said , it was a clunk like it was under pressure , but as mentioned , it was not and the wheels were straight and not touching anything , but it was like the key jammed up , until I figured out it had to be pulled out slightly (1/16th or 1/8th of a inch) then it works like "normal"

EDIT:

OK , this is weird ... I just looked for and found my "spare" key , after you asked if I had tried it , it looks to be not really used ..... So I put it in and it kind of stuck as well , but not as bad , but freed up slightly and I was able to turn it without pulling it out any , but it took some force , then I pulled it and reinserted it , it was easier this time , but still under a bind , I did this 4 more times , each time it got easier , till it was like "normal" ..... So I went and got my "regular" key , I stuck it in , and it was kind of tight like the second key , but not as tight as it was as far as being able to turn it when this first happened , it was kind of like both keys were misaligned with the detents , but cleaned up as you used them , now , my old key works as it should after several tries , but as mentioned , I had tried several times before trying the "spare" key and it would not budge unless I slightly pulled it out ...... but now , I do not need to pull it out slightly and it is working about like it originally was before all this .......Ideas ???

Is the key worn slightly ?? , is the ignition itself the issue ?? , as it seems to be whether temporary or otherwise , ....now fixed after I tried the other key as you suggested

Should I spray some WD-40 in it (or something else to free up the lock without screwing it up ??)

 

It does sound like the tumblers are sticking in the lock cylinder. If you don't have any lock lube handy, WD40 would probably work. Maybe try putting some on the key and working the ignition to see if it frees up. If not then I would spray a little into the cylinder.

 

OK , thanks for the reply again ..... I will get some lock spray tomorrow , as I was thinking about it and think the WD might be a bit too "wet" (I am guessing the lock spray won't be a fluid as WD is) , so I will run to town tomorrow and see what it does , maybe blow it out with my compressor as well , if there is any debris in there ...... Thanks for the help .....

 

Like a mechanic buddy of mine used to say. "Everything stops working at some point in time - it's an imperfect world and we all know this - however everyone is amazed at the particular time that it happens, and that it happened to them or their stuff!"
You have a 14 year old truck and a 14 year old key. If you drive the truck every day and go two different places every day, that means that key and tumbler have been used 20,000 times! I'm not giving you a hard time, just making an observation.
The best thing for keys and locks is graphite. It comes in a little tube like a very small toothpaste tube. At Home Depot and other places that cut keys, they sell it by the key-cutting machine. Don't expect the "associates" at Home Depot or Lowe's to know what you're talking about, but just look for it. It's a very fine powder that sort of liquifies with friction. If this doesn't work, you can go on ebay and order all new locks for doors, tailgate and ignition that are all keyed alike. You don't need a new ignition switch or a new Ignition switch housing. If you can't get it working correctly, you need a new ignition lock cylinder. Here's a video that might help. It's not for a Colorado, but pretty much the same and you only need to watch the first half of the video.
https://youtu.be/d5jQ6uLXt58

 

Thanks ..... looks simple enough if I need to do it ....