I went out to Indian Valley Resevoir to do some camping and wheeling (with some gun shooting mixed in).

I drove behind some guys and sucked in a lot of dust, plus did a few river crossings (above the wheels/tires).

I noticed the next day that my truck was idling really high. Cold Idle was 2000 RPM, warm idle was about 1100 RPM. Before this trip, I was idling at 1200 and 650 respectively.

I thought that maybe the K&N let some dirt by, so I took off the MAF (mass air flow) sensor and cleaned it with alcohol and qtips.

It seemed to fix the issue. I guess the sensor thought less air was being passed, so it leaned out the truck, causing higher idle and bad running.

anyway, just thought I'd share my experience.