Strange Starting Problem

[Sundown94]

Back in May, I had a problem where I would turn the key but the truck would not start. The battery was fine, the lights all worked, the dash lit up, etc. It just wouldn't start. Had it towed to the shop and when we got there, it magically started up as soon as we turned the key. The mechanic said he scanned for codes anyway and that everything seemed to indicate that I needed a new ignition switch, so we put one in.

Last night (about six months later now), I had a similar situation where the the truck would not start. So my wife picked me up (I just locked the doors and left the truck there) and this morning I drove back to the truck with plans to call AAA so that it could be towed to the shop. BUT, I put the key in and it started right up. So I drove it to the shop and the mechanic is going to try reading codes again.

Here is what is similar (IMO) to both cases: 1) the truck decides to start after I leave it alone for some period of time...so in the first case, it started after it was towed to the shop, while in the second case it started after I left it in the parking lot over night. 2) in both cases, I had only started the truck and drove it a short distance (about 1 mile/5 minutes) and then I had the problem starting it afterwards.

Is this really a problem with the ignition switch, or is it related to something else such as the security system? I mean, if it was the ignition switch, why would it magically start after just sitting there untouched over night? Instead, I am wondering if the security system encountered a problem and has some kind of reset period (like maybe an hour needs to go by and then it resets itself or something). The battery was definitely not dead (and just to be sure, I did try jump starting the truck before I gave up last night). Any ideas???

Thanks!
Steve-