2001 Xterra - Runs with rough idle and stalling out at stoplights and while coming to a stop. Cranks back up and keeps going after shut off. During the last month we have replaced Knock Sensor, timing belt, replaced plugs and wires and it's on a 2nd new distributor in 4 weeks (changed out after code kept coming back). Just got it back with the SES light finally off. Drove it maybe 20 miles, came to a stop and it lost RPMs and started running rough again. Running out of ideas. Mechanic is pretty familiar with Nissan and is a really great mechanic, but it has all of us at a loss. He said he checked the MAF sensor and it seems to be ok. Any ideas would be greatly appreciated. For some reason I keep thinking it is that MAF sensor, but that is just a gut feeling due to researching the symptoms our X is having. Thanks!!