low idle in drive 2001 Tundra 4.7 4X4 auto

Low idle in drive with the AC off. Feels like engine will go dead at any moment. Seems o.k. with A/C on. Did the disc negative cable thing but didn't help. Also Dealer just did a 60,000 and supposedly did an top engine cleaning or whatever they do and didn't help it. Has new plugs ect(so the dealer says)Forgot to mention it to them as it was doing it before i took it in. Has only died on me twice but never can tell. This seemed to start when the ignition cylinder locked up and I had to drill it out to get the truck home and then dealer replaced ignition switch at the 60,000 service. I thought I may have blown a fuse or something. Any help?????