Strange bog/hesitation upon acceleration
A couple of weeks back I went through a little mud, about 2-3 feet worth. I was in and out of it, and only went through it twice. After my second time through, I got on the highway, and then came to a stoplight. The truck started to idle rough, and dipped to 500 rpms. I've had problems with the IAC before, and the idle was fluctuating with the A/C, so I swapped on a new IAC. The truck started to idle better, but then it developed a hesitation when I start accelerating from a stop. I'll apply the gas, and the truck will move, but it doesn't really go anywhere. After a few seconds it "kicks in" and goes. The funny thing is, the truck runs great when it's cold. It only starts to give me issues when it warms up. I backprobed the TPS, which revealed a dead spot around 1-2K rpms. So I swapped on a new TPS. That seemed to help a little more, but it still occasionally gives me a problem. Anybody have any ideas what it could be? I've heard all kinds of stuff, like coolant temp sensor, bad replacement TPS, etc. Since it runs fine when cold, it seems to me that it's a vacuum leak that opens up when it warms up. There are no codes present, not even pending codes, so i'm kinda just having to throw tests at it hoping that one of these tests gets me somewhere. Just looking for any fresh ideas that may lead me to the actual problem. All help/suggestions are greatly appreciated.