The Nissan Path

I have a 2005 pathfinder with an odd quirk. I usually get a high idle (around 1000 RPMs) when its rainy outside. While driving, if I let off the accelerator, the RPMs settle but then jumps back to 1000 RPMS. It makes for jerky driving. When coming to a stop, you can feel the transmission downshifting, and the engine still pulling. This is sometimes experienced when the A/C is on and fair weather.

sounds like a vacuum leak to me. we were replacing a part on my 05 and forgot to replace a vacuum line. when we started the engine, it had a high idle of about 1500 for 15 seconds, then would drop to 1000..after another 15 seconds or so, it would jump back to 1500. initially thought it was the throttle position sensor going bad. there were no codes thrown with that vacuum leak for the 5 minutes we had it running.