kjs7v

I own a '97 4runner w/115k miles and recently have been having some hesitation problems. The hesitation does not happen regularly, sometimes when I am traveling at a constant speed the RPM's will even drop by 500 or so and the car will slow for 1.5 seconds and then the RPM's will bounce back. I have ran seafoam through the engine and in the fuel. THere are these three wires on the top of the engine, one i believe is a throttle wire (when i move it the rpm's go up). All three wires are not very tight. Could that be the problem? Also, my car has some water leaking out of the exhaust pipe, why is that? I am a novice, actually, not even that. I just don't want to get screwed. Can someone point me in the right direction? My mechanic says that this is normal, can that be? The 4runner is a 4wd. Please help...