Hey all newbie here so patience please. Bought a 2000 xterra couple of months ago and love it. Haven't used the 4wd since I bought it till last night. While driving I started hearing a tinging noise like something was hitting the under body. Then sporadically my gas pedal or under my gas pedal would grind/pulsate. Pulsations felt like something pushing the gas pedal out as i pushed in. Hope this description makes sense kinda hard to describe. I'm not sure if this has anything to do with me using 4wd. Could this have something to do with drive shaft or CV? Has anyone had this before? Any help would be great!